polish: extract inline CSS, add connection status, panel macro, favicon, ollama cache, toast system (#164)

Major:
- Extract all inline <style> blocks from 22 Jinja2 templates into
  static/css/mission-control.css — single cacheable stylesheet
- Add tox lint check that fails on inline <style> in templates

Minor:
1. Connection status indicator in topbar (green/amber/red dot) reflecting
   WebSocket + Ollama reachability, with auto-reconnect
2. Jinja2 {% macro panel(title) %} in macros.html — eliminates repeated
   .card.mc-panel markup; index.html converted as example
3. SVG favicon (purple T + orange dot)
4. 30-second TTL cache on _check_ollama() to avoid blocking the event loop
   on every health poll (asyncio.to_thread was already in place)
5. Toast notification system (McToast.show) for transient status messages —
   wired into connection status for Ollama/WebSocket state changes

Enforcement:
- CLAUDE.md updated with conventions 11-14 (no inline CSS, use panel macro,
  use toasts, never block the event loop)
- tox lint + pre-push environments now fail on inline <style> blocks

https://claude.ai/code/session_014FQ785MQdyJQ4BAXrRSo9w

Co-authored-by: Claude <noreply@anthropic.com>

src/dashboard/templates/macros.html

@@ -0,0 +1,28 @@
+{# ── Reusable component macros ─────────────────────────────
+   Usage:
+     {% from "macros.html" import panel %}
+     {% call panel("SYSTEM HEALTH") %}
+       <p>Content here</p>
+     {% endcall %}
+
+   Optional kwargs:
+     id        – element id for HTMX targeting
+     classes   – extra CSS classes on the outer card
+     hx_get    – HTMX polling endpoint
+     hx_trigger – HTMX trigger (default: none)
+     hx_target – HTMX swap target (default: "this")
+     hx_swap   – HTMX swap strategy (default: "innerHTML")
+#}
+
+{% macro panel(title, id="", classes="", hx_get="", hx_trigger="", hx_target="this", hx_swap="innerHTML") %}
+<div class="card mc-panel {{ classes }}"
+  {%- if id %} id="{{ id }}"{% endif %}
+  {%- if hx_get %} hx-get="{{ hx_get }}"{% endif %}
+  {%- if hx_trigger %} hx-trigger="{{ hx_trigger }}"{% endif %}
+  {%- if hx_get %} hx-target="{{ hx_target }}" hx-swap="{{ hx_swap }}"{% endif %}>
+  <div class="card-header mc-panel-header">// {{ title }}</div>
+  <div class="card-body p-3">
+    {{ caller() }}
+  </div>
+</div>
+{% endmacro %}