refactor: Break up scorecards.py — two functions over 100 lines each

Extract shared logic into helpers:
- _parse_period(): Period parsing with fallback
- _format_token_display(): Token formatting with +/-
- _format_token_class(): CSS class based on token sign
- _build_patterns_html(): Pattern section HTML
- _build_narrative_html(): Narrative bullets HTML
- _build_metrics_row_html(): Metrics row HTML
- _render_scorecard_panel(): Single panel renderer
- _render_empty_scorecard(): Empty state renderer
- _render_error_scorecard(): Error state renderer
- _render_single_panel_wrapper(): Single panel wrapper
- _render_all_panels_grid(): Grid layout for all panels

Before:
- agent_scorecard_panel(): 108 lines
- all_scorecard_panels(): 106 lines

After:
- agent_scorecard_panel(): 26 lines
- all_scorecard_panels(): 26 lines

All helpers have docstrings. All 49 tests pass.

Fixes #1127

src/dashboard/routes/scorecards.py

@@ -10,6 +10,7 @@ from fastapi.responses import HTMLResponse, JSONResponse
 
 from dashboard.services.scorecard_service import (
     PeriodType,
+    ScorecardSummary,
     generate_all_scorecards,
     generate_scorecard,
     get_tracked_agents,
@@ -26,6 +27,216 @@ def _format_period_label(period_type: PeriodType) -> str:
     return "Daily" if period_type == PeriodType.daily else "Weekly"
 
 
+def _parse_period(period: str) -> PeriodType:
+    """Parse period string into PeriodType, defaulting to daily on invalid input.
+
+    Args:
+        period: The period string ('daily' or 'weekly')
+
+    Returns:
+        PeriodType.daily or PeriodType.weekly
+    """
+    try:
+        return PeriodType(period.lower())
+    except ValueError:
+        return PeriodType.daily
+
+
+def _format_token_display(token_net: int) -> str:
+    """Format token net value with +/- prefix for display.
+
+    Args:
+        token_net: The net token value
+
+    Returns:
+        Formatted string with + prefix for positive values
+    """
+    return f"{'+' if token_net > 0 else ''}{token_net}"
+
+
+def _format_token_class(token_net: int) -> str:
+    """Get CSS class for token net value based on sign.
+
+    Args:
+        token_net: The net token value
+
+    Returns:
+        'text-success' for positive/zero, 'text-danger' for negative
+    """
+    return "text-success" if token_net >= 0 else "text-danger"
+
+
+def _build_patterns_html(patterns: list[str]) -> str:
+    """Build HTML for patterns section if patterns exist.
+
+    Args:
+        patterns: List of pattern strings
+
+    Returns:
+        HTML string for patterns section or empty string
+    """
+    if not patterns:
+        return ""
+
+    patterns_list = "".join([f"<li>{p}</li>" for p in patterns])
+    return f"""
+    <div class="mt-3">
+        <h6>Patterns</h6>
+        <ul class="list-unstyled text-info">
+            {patterns_list}
+        </ul>
+    </div>
+    """
+
+
+def _build_narrative_html(bullets: list[str]) -> str:
+    """Build HTML for narrative bullets.
+
+    Args:
+        bullets: List of narrative bullet strings
+
+    Returns:
+        HTML string with list items
+    """
+    return "".join([f"<li>{b}</li>" for b in bullets])
+
+
+def _build_metrics_row_html(metrics: dict) -> str:
+    """Build HTML for the metrics summary row.
+
+    Args:
+        metrics: Dictionary with PRs, issues, tests, and token metrics
+
+    Returns:
+        HTML string for the metrics row
+    """
+    prs_opened = metrics["prs_opened"]
+    prs_merged = metrics["prs_merged"]
+    pr_merge_rate = int(metrics["pr_merge_rate"] * 100)
+    issues_touched = metrics["issues_touched"]
+    tests_affected = metrics["tests_affected"]
+    token_net = metrics["token_net"]
+
+    token_class = _format_token_class(token_net)
+    token_display = _format_token_display(token_net)
+
+    return f"""
+    <div class="row text-center small">
+        <div class="col">
+            <div class="text-muted">PRs</div>
+            <div class="fw-bold">{prs_opened}/{prs_merged}</div>
+            <div class="text-muted" style="font-size: 0.75rem;">
+                {pr_merge_rate}% merged
+            </div>
+        </div>
+        <div class="col">
+            <div class="text-muted">Issues</div>
+            <div class="fw-bold">{issues_touched}</div>
+        </div>
+        <div class="col">
+            <div class="text-muted">Tests</div>
+            <div class="fw-bold">{tests_affected}</div>
+        </div>
+        <div class="col">
+            <div class="text-muted">Tokens</div>
+            <div class="fw-bold {token_class}">{token_display}</div>
+        </div>
+    </div>
+    """
+
+
+def _render_scorecard_panel(
+    agent_id: str,
+    period_type: PeriodType,
+    data: dict,
+) -> str:
+    """Render HTML for a single scorecard panel.
+
+    Args:
+        agent_id: The agent ID
+        period_type: Daily or weekly period
+        data: Scorecard data dictionary with metrics, patterns, narrative_bullets
+
+    Returns:
+        HTML string for the scorecard panel
+    """
+    patterns_html = _build_patterns_html(data.get("patterns", []))
+    bullets_html = _build_narrative_html(data.get("narrative_bullets", []))
+    metrics_row = _build_metrics_row_html(data["metrics"])
+
+    return f"""
+    <div class="card mc-panel">
+        <div class="card-header d-flex justify-content-between align-items-center">
+            <h5 class="card-title mb-0">{agent_id.title()}</h5>
+            <span class="badge bg-secondary">{_format_period_label(period_type)}</span>
+        </div>
+        <div class="card-body">
+            <ul class="list-unstyled mb-3">
+                {bullets_html}
+            </ul>
+            {metrics_row}
+            {patterns_html}
+        </div>
+    </div>
+    """
+
+
+def _render_empty_scorecard(agent_id: str) -> str:
+    """Render HTML for an empty scorecard (no activity).
+
+    Args:
+        agent_id: The agent ID
+
+    Returns:
+        HTML string for the empty scorecard panel
+    """
+    return f"""
+    <div class="card mc-panel">
+        <h5 class="card-title">{agent_id.title()}</h5>
+        <p class="text-muted">No activity recorded for this period.</p>
+    </div>
+    """
+
+
+def _render_error_scorecard(agent_id: str, error: str) -> str:
+    """Render HTML for a scorecard that failed to load.
+
+    Args:
+        agent_id: The agent ID
+        error: Error message string
+
+    Returns:
+        HTML string for the error scorecard panel
+    """
+    return f"""
+    <div class="card mc-panel border-danger">
+        <h5 class="card-title">{agent_id.title()}</h5>
+        <p class="text-danger">Error loading scorecard: {error}</p>
+    </div>
+    """
+
+
+def _render_single_panel_wrapper(
+    agent_id: str,
+    period_type: PeriodType,
+    scorecard: ScorecardSummary | None,
+) -> str:
+    """Render a complete scorecard panel with wrapper div for single panel view.
+
+    Args:
+        agent_id: The agent ID
+        period_type: Daily or weekly period
+        scorecard: ScorecardSummary object or None
+
+    Returns:
+        HTML string for the complete panel
+    """
+    if scorecard is None:
+        return _render_empty_scorecard(agent_id)
+
+    return _render_scorecard_panel(agent_id, period_type, scorecard.to_dict())
+
+
 @router.get("/api/agents")
 async def list_tracked_agents() -> dict[str, list[str]]:
     """Return the list of tracked agent IDs.
@@ -149,99 +360,50 @@ async def agent_scorecard_panel(
     Returns:
         HTML panel with scorecard content
     """
-    try:
-        period_type = PeriodType(period.lower())
-    except ValueError:
-        period_type = PeriodType.daily
+    period_type = _parse_period(period)
 
     try:
         scorecard = generate_scorecard(agent_id, period_type)
-
-        if scorecard is None:
-            return HTMLResponse(
-                content=f"""
-                <div class="card mc-panel">
-                    <h5 class="card-title">{agent_id.title()}</h5>
-                    <p class="text-muted">No activity recorded for this period.</p>
-                </div>
-                """,
-                status_code=200,
-            )
-
-        data = scorecard.to_dict()
-
-        # Build patterns HTML
-        patterns_html = ""
-        if data["patterns"]:
-            patterns_list = "".join([f"<li>{p}</li>" for p in data["patterns"]])
-            patterns_html = f"""
-            <div class="mt-3">
-                <h6>Patterns</h6>
-                <ul class="list-unstyled text-info">
-                    {patterns_list}
-                </ul>
-            </div>
-            """
-
-        # Build bullets HTML
-        bullets_html = "".join([f"<li>{b}</li>" for b in data["narrative_bullets"]])
-
-        # Build metrics summary
-        metrics = data["metrics"]
-
-        html_content = f"""
-        <div class="card mc-panel">
-            <div class="card-header d-flex justify-content-between align-items-center">
-                <h5 class="card-title mb-0">{agent_id.title()}</h5>
-                <span class="badge bg-secondary">{_format_period_label(period_type)}</span>
-            </div>
-            <div class="card-body">
-                <ul class="list-unstyled mb-3">
-                    {bullets_html}
-                </ul>
-                
-                <div class="row text-center small">
-                    <div class="col">
-                        <div class="text-muted">PRs</div>
-                        <div class="fw-bold">{metrics["prs_opened"]}/{metrics["prs_merged"]}</div>
-                        <div class="text-muted" style="font-size: 0.75rem;">
-                            {int(metrics["pr_merge_rate"] * 100)}% merged
-                        </div>
-                    </div>
-                    <div class="col">
-                        <div class="text-muted">Issues</div>
-                        <div class="fw-bold">{metrics["issues_touched"]}</div>
-                    </div>
-                    <div class="col">
-                        <div class="text-muted">Tests</div>
-                        <div class="fw-bold">{metrics["tests_affected"]}</div>
-                    </div>
-                    <div class="col">
-                        <div class="text-muted">Tokens</div>
-                        <div class="fw-bold {"text-success" if metrics["token_net"] >= 0 else "text-danger"}">
-                            {"+" if metrics["token_net"] > 0 else ""}{metrics["token_net"]}
-                        </div>
-                    </div>
-                </div>
-                
-                {patterns_html}
-            </div>
-        </div>
-        """
-
+        html_content = _render_single_panel_wrapper(agent_id, period_type, scorecard)
         return HTMLResponse(content=html_content)
 
     except Exception as exc:
         logger.error("Failed to render scorecard panel for %s: %s", agent_id, exc)
-        return HTMLResponse(
-            content=f"""
-            <div class="card mc-panel border-danger">
-                <h5 class="card-title">{agent_id.title()}</h5>
-                <p class="text-danger">Error loading scorecard: {str(exc)}</p>
-            </div>
-            """,
-            status_code=200,
+        return HTMLResponse(content=_render_error_scorecard(agent_id, str(exc)))
+
+
+def _render_all_panels_grid(
+    scorecards: list[ScorecardSummary],
+    period_type: PeriodType,
+) -> str:
+    """Render all scorecard panels in a grid layout.
+
+    Args:
+        scorecards: List of scorecard summaries
+        period_type: Daily or weekly period
+
+    Returns:
+        HTML string with all panels in a grid
+    """
+    panels: list[str] = []
+    for scorecard in scorecards:
+        panel_html = _render_scorecard_panel(
+            scorecard.agent_id,
+            period_type,
+            scorecard.to_dict(),
         )
+        # Wrap each panel in a grid column
+        wrapped = f'<div class="col-md-6 col-lg-4 mb-3">{panel_html}</div>'
+        panels.append(wrapped)
+
+    return f"""
+    <div class="row">
+        {"".join(panels)}
+    </div>
+    <div class="text-muted small mt-2">
+        Generated: {datetime.now().strftime("%Y-%m-%d %H:%M:%S UTC")}
+    </div>
+    """
 
 
 @router.get("/all/panels", response_class=HTMLResponse)
@@ -258,96 +420,15 @@ async def all_scorecard_panels(
     Returns:
         HTML with all scorecard panels
     """
-    try:
-        period_type = PeriodType(period.lower())
-    except ValueError:
-        period_type = PeriodType.daily
+    period_type = _parse_period(period)
 
     try:
         scorecards = generate_all_scorecards(period_type)
-
-        panels: list[str] = []
-        for scorecard in scorecards:
-            data = scorecard.to_dict()
-
-            # Build patterns HTML
-            patterns_html = ""
-            if data["patterns"]:
-                patterns_list = "".join([f"<li>{p}</li>" for p in data["patterns"]])
-                patterns_html = f"""
-                <div class="mt-3">
-                    <h6>Patterns</h6>
-                    <ul class="list-unstyled text-info">
-                        {patterns_list}
-                    </ul>
-                </div>
-                """
-
-            # Build bullets HTML
-            bullets_html = "".join([f"<li>{b}</li>" for b in data["narrative_bullets"]])
-            metrics = data["metrics"]
-
-            panel_html = f"""
-            <div class="col-md-6 col-lg-4 mb-3">
-                <div class="card mc-panel">
-                    <div class="card-header d-flex justify-content-between align-items-center">
-                        <h5 class="card-title mb-0">{scorecard.agent_id.title()}</h5>
-                        <span class="badge bg-secondary">{_format_period_label(period_type)}</span>
-                    </div>
-                    <div class="card-body">
-                        <ul class="list-unstyled mb-3">
-                            {bullets_html}
-                        </ul>
-                        
-                        <div class="row text-center small">
-                            <div class="col">
-                                <div class="text-muted">PRs</div>
-                                <div class="fw-bold">{metrics["prs_opened"]}/{metrics["prs_merged"]}</div>
-                                <div class="text-muted" style="font-size: 0.75rem;">
-                                    {int(metrics["pr_merge_rate"] * 100)}% merged
-                                </div>
-                            </div>
-                            <div class="col">
-                                <div class="text-muted">Issues</div>
-                                <div class="fw-bold">{metrics["issues_touched"]}</div>
-                            </div>
-                            <div class="col">
-                                <div class="text-muted">Tests</div>
-                                <div class="fw-bold">{metrics["tests_affected"]}</div>
-                            </div>
-                            <div class="col">
-                                <div class="text-muted">Tokens</div>
-                                <div class="fw-bold {"text-success" if metrics["token_net"] >= 0 else "text-danger"}">
-                                    {"+" if metrics["token_net"] > 0 else ""}{metrics["token_net"]}
-                                </div>
-                            </div>
-                        </div>
-                        
-                        {patterns_html}
-                    </div>
-                </div>
-            </div>
-            """
-            panels.append(panel_html)
-
-        html_content = f"""
-        <div class="row">
-            {"".join(panels)}
-        </div>
-        <div class="text-muted small mt-2">
-            Generated: {datetime.now().strftime("%Y-%m-%d %H:%M:%S UTC")}
-        </div>
-        """
-
+        html_content = _render_all_panels_grid(scorecards, period_type)
         return HTMLResponse(content=html_content)
 
     except Exception as exc:
         logger.error("Failed to render all scorecard panels: %s", exc)
         return HTMLResponse(
-            content=f"""
-            <div class="alert alert-danger">
-                Error loading scorecards: {str(exc)}
-            </div>
-            """,
-            status_code=200,
+            content=f'<div class="alert alert-danger">Error loading scorecards: {exc}</div>'
         )