refactor(mcp): single tool registry, SDK 1.30.0, deprecate duplicate servers

Audit #1 consolidation (board job b0339752):
- src/shared/tool-registry.ts is now the canonical tool surface (26 tools:
  names, descriptions, JSON-Schema contracts). The stdio server consumes it;
  inline tool defs in server files are gone.
- Canonical servers decided and documented: stdio (src/local/mcp-server.ts,
  ships as @virsanghavi/axis-server) for local, and the Streamable-HTTP
  adapter (axis-frontend app/api/mcp) for hosted.
- @modelcontextprotocol/sdk 0.6.0 -> 1.30.0 in both manifests; low-level
  Server API verified compatible (129/129 tests, JSON-RPC probe returns all
  26 tools from the rebuilt bundle).
- src/local/server.ts (Express/SSE) and src/api/index.ts (duplicate Hono)
  marked @deprecated with startup warnings; physical removal tracked by the
  "Remove Express" board job which depends on this decision.