feat(pro): generalize pro tier to multi-surface extension points

Move the pro mount decnet/services/pro/ -> decnet/pro/ so the Professional tier
can contribute to more than honeypots. The core wires each surface only when
decnet/pro/ is present (absence stays the entitlement gate):

* services  — registry scans decnet/pro/services/ (was decnet/services/pro/)
* API routes — decnet/pro/routes.py exposes ROUTERS, mounted under /api/v1
* web pages  — Vite aliases @pro to the pro frontend (community -> empty stub),
               App.tsx maps proRoutes into <Route>s, Layout renders a
               PROFESSIONAL nav group; both tree-shake out of the community build

Frontend gate mirrors the existing VITE_DECNET_DEVELOPER tree-shake pattern.
Tests: registry + router seams (backend), empty-stub contract (frontend).

decnet_web/tsconfig.app.json

@@ -10,6 +10,12 @@
     /* Bundler mode */
     "moduleResolution": "bundler",
     "allowImportingTsExtensions": true,
+
+    /* `@pro` resolves to the empty community stub for type-checking. The
+       Professional build overrides this to decnet/pro/web/index.tsx. Must mirror
+       the Vite alias in vite.config.ts. (bundler resolution => no baseUrl.) */
+    "paths": { "@pro": ["./src/pro/stub.ts"] },
+
     "verbatimModuleSyntax": true,
     "moduleDetection": "force",
     "noEmit": true,