Implement WP-0011 hub service, CLI, and deployment artifacts

Add FederationHubAPI spec, hub registration schema, FastAPI hub with SQLite
persistence, reuse-surface hub CLI client, Dockerfile, and hub tests. Activate
workplan; T05 deploy and T06 ops docs remain open pending railiance01 cutover.

pyproject.toml

@@ -9,17 +9,21 @@ description = "Capability registry tooling for reuse-surface"
 readme = "README.md"
 requires-python = ">=3.11"
 dependencies = [
+  "fastapi>=0.110",
   "jsonschema>=4.0",
   "pyyaml>=6.0",
+  "uvicorn[standard]>=0.27",
 ]
 
 [project.optional-dependencies]
 dev = [
+  "httpx>=0.27",
   "pytest>=8.0",
 ]
 
 [project.scripts]
 reuse-surface = "reuse_surface.cli:main"
+reuse-surface-hub = "reuse_surface.hub.app:main"
 
 [tool.setuptools.packages.find]
 where = ["."]