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/mcp_client.py

@@ -54,3 +54,46 @@ async def get_worklog(
 
 async def get_standup(days: int = 2, context: str = "egmont") -> Dict[str, Any]:
     return await _call_tool("generate_standup", {"days": days, "context": context})
+
+
+async def list_knowledge(category: Optional[str] = None, tag: Optional[str] = None) -> Dict[str, Any]:
+    args: Dict[str, Any] = {}
+    if category:
+        args["category"] = category
+    if tag:
+        args["tag"] = tag
+    return await _call_tool("list_knowledge", args)
+
+
+async def get_knowledge(storage_filename: str) -> Dict[str, Any]:
+    return await _call_tool("get_knowledge", {"storage_filename": storage_filename, "include_metadata": False})
+
+
+async def list_howtos() -> Dict[str, Any]:
+    return await _call_tool("list_howtos", {})
+
+
+async def get_howto(filename: str) -> Dict[str, Any]:
+    return await _call_tool("get_howto_content", {"filename": filename})
+
+
+async def list_agents(domain: Optional[str] = None) -> Dict[str, Any]:
+    args: Dict[str, Any] = {}
+    if domain:
+        args["domain"] = domain
+    return await _call_tool("get_agent", args)
+
+
+async def get_agent(name: str) -> Dict[str, Any]:
+    return await _call_tool("get_agent", {"name": name})
+
+
+async def list_skills(domain: Optional[str] = None) -> Dict[str, Any]:
+    args: Dict[str, Any] = {}
+    if domain:
+        args["domain"] = domain
+    return await _call_tool("get_skill", args)
+
+
+async def get_skill(name: str) -> Dict[str, Any]:
+    return await _call_tool("get_skill", {"name": name})