feat: Projects tab, 4-tab dashboard, full knowledge browser

- Add projects router (Redis projects + workcontexts merged)
- Register projects router in main.py
- Extend knowledge router: howtos, agents, skills via MCP proxy
- Extend mcp_client: list/get howtos, agents, skills
- Rewrite dashboard.html: 4 tabs (Taskz/Worklog/Projects/Knowledge)
  - Taskz: sidebar board list + Kanban columns with task modal
  - Worklog: context/days picker + standup button
  - Projects: context filter sidebar + work context display
  - Knowledge: 6 sub-tabs (docs/howtos/agents/skills/adrs/memories)
    with markdown rendering via marked.js

app/routers/projects.py

@@ -0,0 +1,61 @@
+"""Projects router — registered git repos + work contexts from Redis."""
+
+from __future__ import annotations
+
+from typing import Optional
+
+from fastapi import APIRouter
+
+from app.redis_client import get_redis, list_projects, list_workcontexts, PROJECT_KEY_PREFIX, WORKCONTEXT_KEY_PREFIX
+
+router = APIRouter(prefix="/api/v1", tags=["projects"])
+
+
+@router.get("/projects")
+def api_list_projects(context: Optional[str] = None, q: Optional[str] = None):
+    r = get_redis()
+    projects = list_projects(r, context=context)
+
+    # Merge in work contexts (keyed by path)
+    wc_keys = r.keys(f"{WORKCONTEXT_KEY_PREFIX}*")
+    import json
+    work_contexts: dict = {}
+    for key in wc_keys:
+        raw = r.get(key)
+        if raw:
+            try:
+                path = key[len(WORKCONTEXT_KEY_PREFIX):]
+                work_contexts[path] = json.loads(raw)
+            except Exception:
+                pass
+
+    # Attach work context and apply search filter
+    result = []
+    for p in projects:
+        path = p.get("path", "")
+        p["work_context"] = work_contexts.get(path)
+        if q and q.lower() not in (p.get("name", "") + p.get("path", "") + " ".join(p.get("tags", []))).lower():
+            continue
+        result.append(p)
+
+    # Sort: projects with recent work context first
+    result.sort(
+        key=lambda p: (
+            p["work_context"]["saved_at"] if p.get("work_context") else "",
+        ),
+        reverse=True,
+    )
+
+    # Context breakdown
+    contexts = {}
+    for p in result:
+        c = p.get("context", "unknown")
+        contexts[c] = contexts.get(c, 0) + 1
+
+    return {"projects": result, "total": len(result), "contexts": contexts}
+
+
+@router.get("/workcontexts")
+def api_list_workcontexts():
+    r = get_redis()
+    return {"contexts": list_workcontexts(r)}