chore: remove Express/SSE and duplicate Hono servers from the shipped surface

Audit #12 (board job c427d5fe), following the consolidation decision:
- Delete src/local/server.ts (Express+SSE MCP duplicate) and
  src/api/index.ts (legacy Hono API duplicated by axis-frontend /api/v1).
- Drop express, @types/express, hono, and zod from dependencies (zod was
  only imported by the deleted Hono server); lockfile refreshed.
- Drop start:server / start:api / dev scripts that ran the dead servers.
- Remove Dockerfile, docker-compose.yml, .dockerignore — they existed only
  to containerize the two deleted servers.
- README: architecture section now names the real surfaces (stdio server +
  hosted useaxis.dev), RAG examples point at https://useaxis.dev/api/v1.

Verified: tsc clean on touched files, 149/150 bun tests pass (the one
failure is tests/atomic-file.test.ts, in-flight work by another session),
rebuilt bundle still answers tools/list.