feat(01-04): FastAPI portal API endpoints with tenant/agent CRUD and auth

- Add packages/shared/shared/api/portal.py with APIRouter at /api/portal
- POST /auth/verify validates bcrypt credentials against portal_users table
- POST /auth/register creates new portal users with hashed passwords
- Tenant CRUD: GET/POST /tenants, GET/PUT/DELETE /tenants/{id}
- Agent CRUD: full CRUD under /tenants/{tenant_id}/agents/{id}
- Agent endpoints set RLS current_tenant_id context for policy compliance
- Pydantic v2 schemas with slug validation (lowercase, hyphens, 2-50 chars)
- Add bcrypt>=4.0.0 dependency to konstruct-shared
- Integration tests: 38 tests covering all CRUD, validation, and isolation

uv.lock

@@ -1205,6 +1205,7 @@ name = "konstruct-orchestrator"
 version = "0.1.0"
 source = { editable = "packages/orchestrator" }
 dependencies = [
+    { name = "celery", extra = ["redis"] },
     { name = "fastapi", extra = ["standard"] },
     { name = "httpx" },
     { name = "konstruct-shared" },
@@ -1212,6 +1213,7 @@ dependencies = [
 
 [package.metadata]
 requires-dist = [
+    { name = "celery", extras = ["redis"], specifier = ">=5.4.0" },
     { name = "fastapi", extras = ["standard"], specifier = ">=0.115.0" },
     { name = "httpx", specifier = ">=0.28.0" },
     { name = "konstruct-shared", editable = "packages/shared" },