refactor: break up _gather_system_snapshot() into focused helpers

Extract 5 helpers from the 86-line method:
- _snapshot_time() — local clock formatting
- _snapshot_thought_count() — today's thought count query
- _snapshot_chat_activity() — recent chat lines
- _snapshot_task_queue() — task queue summary
- _snapshot_workspace() — workspace update lines

Each helper is independently error-handled, keeping the same
graceful-degradation guarantees.

Fixes #540

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/timmy/thinking.py

@@ -772,23 +772,19 @@ class ThinkingEngine:
         except Exception as exc:
             logger.debug("Thought issue filing skipped: %s", exc)
 
-    def _gather_system_snapshot(self) -> str:
-        """Gather lightweight real system state for grounding thoughts in reality.
+    # -- system-snapshot helpers ----------------------------------------
 
-        Returns a short multi-line string with current time, thought count,
-        recent chat activity, and task queue status. Never crashes — every
-        section is independently try/excepted.
-        """
-        parts: list[str] = []
-
-        # Current local time
+    def _snapshot_time(self) -> tuple[datetime, str]:
+        """Return (now, formatted-time-line) for the local clock."""
         now = datetime.now().astimezone()
         tz = now.strftime("%Z") or "UTC"
-        parts.append(
+        line = (
             f"Local time: {now.strftime('%I:%M %p').lstrip('0')} {tz}, {now.strftime('%A %B %d')}"
         )
+        return now, line
 
-        # Thought count today (cheap DB query)
+    def _snapshot_thought_count(self, now: datetime) -> str | None:
+        """Return today's thought count as a display string, or *None*."""
         try:
             today_start = now.replace(hour=0, minute=0, second=0, microsecond=0)
             with _get_conn(self._db_path) as conn:
@@ -796,27 +792,30 @@ class ThinkingEngine:
                     "SELECT COUNT(*) as c FROM thoughts WHERE created_at >= ?",
                     (today_start.isoformat(),),
                 ).fetchone()["c"]
-            parts.append(f"Thoughts today: {count}")
+            return f"Thoughts today: {count}"
         except Exception as exc:
             logger.debug("Thought count query failed: %s", exc)
-            pass
+            return None
 
-        # Recent chat activity (in-memory, no I/O)
+    def _snapshot_chat_activity(self) -> list[str]:
+        """Return chat-activity lines (may be empty)."""
         try:
             from infrastructure.chat_store import message_log
 
             messages = message_log.all()
             if messages:
-                parts.append(f"Chat messages this session: {len(messages)}")
                 last = messages[-1]
-                parts.append(f'Last chat ({last.role}): "{last.content[:80]}"')
-            else:
-                parts.append("No chat messages this session")
+                return [
+                    f"Chat messages this session: {len(messages)}",
+                    f'Last chat ({last.role}): "{last.content[:80]}"',
+                ]
+            return ["No chat messages this session"]
         except Exception as exc:
             logger.debug("Chat activity query failed: %s", exc)
-            pass
+            return []
 
-        # Task queue (lightweight DB query)
+    def _snapshot_task_queue(self) -> str | None:
+        """Return a one-line task-queue summary, or *None*."""
         try:
             from swarm.task_queue.models import get_task_summary_for_briefing
 
@@ -826,36 +825,62 @@ class ThinkingEngine:
             done = summary.get("completed", 0)
             failed = summary.get("failed", 0)
             if running or pending or done or failed:
-                parts.append(
+                return (
                     f"Tasks: {running} running, {pending} pending, "
                     f"{done} completed, {failed} failed"
                 )
         except Exception as exc:
             logger.debug("Task queue query failed: %s", exc)
-            pass
+        return None
 
-        # Workspace updates (file-based communication with Hermes)
+    def _snapshot_workspace(self) -> list[str]:
+        """Return workspace-update lines (may be empty)."""
         try:
             from timmy.workspace import workspace_monitor
 
             updates = workspace_monitor.get_pending_updates()
+            lines: list[str] = []
             new_corr = updates.get("new_correspondence")
             new_inbox = updates.get("new_inbox_files", [])
 
             if new_corr:
-                # Count entries (assuming each entry starts with a timestamp or header)
-                line_count = len([line for line in new_corr.splitlines() if line.strip()])
-                parts.append(
+                line_count = len([ln for ln in new_corr.splitlines() if ln.strip()])
+                lines.append(
                     f"Workspace: {line_count} new correspondence entries (latest from: Hermes)"
                 )
             if new_inbox:
                 files_str = ", ".join(new_inbox[:5])
                 if len(new_inbox) > 5:
                     files_str += f", ... (+{len(new_inbox) - 5} more)"
-                parts.append(f"Workspace: {len(new_inbox)} new inbox files: {files_str}")
+                lines.append(f"Workspace: {len(new_inbox)} new inbox files: {files_str}")
+            return lines
         except Exception as exc:
             logger.debug("Workspace check failed: %s", exc)
-            pass
+            return []
+
+    # -- public snapshot entry point ------------------------------------
+
+    def _gather_system_snapshot(self) -> str:
+        """Gather lightweight real system state for grounding thoughts in reality.
+
+        Returns a short multi-line string with current time, thought count,
+        recent chat activity, and task queue status. Never crashes — every
+        section is independently try/excepted.
+        """
+        now, time_line = self._snapshot_time()
+        parts: list[str] = [time_line]
+
+        thought_line = self._snapshot_thought_count(now)
+        if thought_line:
+            parts.append(thought_line)
+
+        parts.extend(self._snapshot_chat_activity())
+
+        task_line = self._snapshot_task_queue()
+        if task_line:
+            parts.append(task_line)
+
+        parts.extend(self._snapshot_workspace())
 
         return "\n".join(parts) if parts else ""