feat(dashboard): unified workspace hub — cookie auth, 9-state projects, planning chat

Merges workspace.html + ralph.html into a single unified project hub with:
- Cookie-based auth (DASHBOARD_TOKEN, HttpOnly, SameSite=Strict)
- 9-state project badge system (running-ralph/manual, planning, approved,
  pending, blocked, failed, complete, idle) with BUTTONS_FOR_STATE matrix
- SSE realtime + polling fallback, version-based optimistic concurrency (If-Match)
- Planning chat modal (phase stepper, markdown bubbles, 50s+ wait state, auto-resume)
- Propose modal (Variant B: inline Plan-with-Echo checkbox)
- 5-type toast taxonomy (success/info/warning/busy/error, 3px colored left-bar)
- Inter font self-hosted + shared tokens.css design system + DESIGN.md
- src/jsonlock.py (flock helper, sidecar .lock for stable inode)
- src/approved_tasks_cli.py (shell-safe wrapper for cron/ralph.sh)
- 55 new tests (T#1–T#30) + real jsonlock bug fix caught by T#16/T#28
- No emoji anywhere (enforced by test_dashboard_no_emoji.py)

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

dashboard/index.html

@@ -5,6 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <link rel="icon" type="image/svg+xml" href="/echo/favicon.svg">
     <title>Echo · Dashboard</title>
+    <link rel="stylesheet" href="/echo/static/tokens.css">
     <link rel="stylesheet" href="/echo/common.css">
     <script src="https://unpkg.com/lucide@latest/dist/umd/lucide.min.js"></script>
     <script src="/echo/swipe-nav.js"></script>