feat: add web UI project registry and onboarding (#427)

Load projects from versioned webui/data/projects.registry.json with profile
mappings, workflow/schema paths, and read-only onboarding checklist UI.
Seeds Gitea-Tools; exposes /projects, /projects/{id}, and /api/projects.

Closes #427

webui/app.py

@@ -10,6 +10,8 @@ from starlette.responses import HTMLResponse, JSONResponse, Response
 from starlette.routing import Route
 
 from webui.layout import render_page
+from webui.project_registry import find_project, load_registry, registry_to_dict
+from webui.project_views import render_project_detail, render_projects_list
 
 _READ_ONLY_METHODS = frozenset({"GET", "HEAD", "OPTIONS"})
 
@@ -49,10 +51,32 @@ async def health(_request: Request) -> JSONResponse:
 
 
 async def projects(_request: Request) -> HTMLResponse:
-    return _stub_page(
-        "Projects",
-        "Project registry and onboarding model will list configured repos and profiles.",
-    )
+    registry = load_registry()
+    return HTMLResponse(render_projects_list(registry))
+
+
+async def project_detail(request: Request) -> HTMLResponse:
+    project_id = request.path_params["project_id"]
+    registry = load_registry()
+    project = find_project(registry, project_id)
+    if project is None:
+        return HTMLResponse(
+            render_page(
+                title="Project not found",
+                body_html=(
+                    "<h2>Project not found</h2>"
+                    f"<p>No registry entry for <code>{project_id}</code>.</p>"
+                    '<p><a href="/projects">← All projects</a></p>'
+                ),
+            ),
+            status_code=404,
+        )
+    return HTMLResponse(render_project_detail(project))
+
+
+async def api_projects(_request: Request) -> JSONResponse:
+    registry = load_registry()
+    return JSONResponse(registry_to_dict(registry))
 
 
 async def prompts(_request: Request) -> HTMLResponse:
@@ -107,6 +131,8 @@ def create_app() -> Starlette:
             Route("/", home, methods=["GET"]),
             Route("/health", health, methods=["GET"]),
             Route("/projects", projects, methods=["GET"]),
+            Route("/projects/{project_id}", project_detail, methods=["GET"]),
+            Route("/api/projects", api_projects, methods=["GET"]),
             Route("/prompts", prompts, methods=["GET"]),
             Route("/runtime", runtime, methods=["GET"]),
             Route("/audit", audit, methods=["GET"]),