chore(docs): retire dead fable-mcp wheel-distribution refs; untrack docs/superpowers

The old standalone fable-mcp wheel/download flow is gone from code (no route,
no Dockerfile build, no FABLE_MCP_DIST_DIR). Update api-keys-and-mcp,
api-reference, architecture, configuration, development to describe the
in-app HTTP MCP at /mcp (Bearer auth). Untrack the 18 committed
docs/superpowers/ files so the existing .gitignore takes effect.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/architecture.md

@@ -49,16 +49,14 @@ scribe/
 ├── Dockerfile                   # Multi-stage build (Node → Python)
 ├── alembic/                     # Database migrations
 │   └── versions/                # Migration files (idempotent raw SQL)
-├── fable-mcp/                   # Fable MCP server package
-│   └── fable_mcp/
-│       ├── server.py            # FastMCP tool registrations
-│       ├── client.py            # FableClient (httpx wrapper)
-│       └── tools/               # Tool modules (notes, tasks, projects, …)
 ├── src/scribe/
 │   ├── app.py                   # Quart app factory + blueprint registration
 │   ├── config.py                # Config class (reads env vars)
 │   ├── auth.py                  # login_required decorator, session checks
 │   ├── models/                  # SQLAlchemy models
+│   ├── mcp/                      # In-app MCP server (FastMCP, mounted at /mcp)
+│   │   ├── server.py            # FastMCP instance + instructions + Quart mount
+│   │   └── tools/               # Tool modules (notes, tasks, projects, rulebooks, …)
 │   ├── routes/                  # API blueprints (one file per resource)
 │   ├── services/                # Business logic (access, llm, tools, sharing, …)
 │   └── static/                  # Built Vue SPA (generated at Docker build time)
@@ -202,7 +200,7 @@ Permission resolution is centralised in `services/access.py`. `get_project_permi
 | `routes/images.py` | Serve cached images at `/api/images/<id>` |
 | `routes/export.py` | `GET /api/export` — personal Markdown ZIP or JSON array download |
 | `routes/api_keys.py` | API key CRUD (`GET/POST/DELETE /api/api-keys`) |
-| `routes/fable_mcp_dist.py` | `GET /api/fable-mcp/info` + `GET /api/fable-mcp/download` — package distribution |
+| `mcp/server.py` | Mounts the in-app FastMCP server at `/mcp` (streamable HTTP, Bearer auth) |
 | `routes/quick_capture.py` | `POST /api/quick-capture` — single-shot natural language item creation |
 | `routes/search.py` | `GET /api/search` — semantic + keyword hybrid search |
 | `services/auth.py` | `create_user`, `authenticate`, user lookups, password reset tokens, invitation tokens |