Add project-aware chat startup defaults

Make repo-root chat startup native by letting MCP servers carry a default project source for workspace creation. When a chat host starts from a Git checkout, workspace_create can now omit seed_path and inherit the server startup source; explicit --project-path and clean-clone --repo-url/--repo-ref paths are supported as fallbacks.

Add project startup resolution and materialization, surface origin_kind/origin_ref in workspace_seed, update chat-host docs and the repro/fix smoke to use project-aware workspace creation, and switch dist-check to uv run pyro so verification stays stable after uv reinstalls.

Validated with uv lock, focused startup/server/CLI pytest coverage, UV_CACHE_DIR=.uv-cache make check, UV_CACHE_DIR=.uv-cache make dist-check, and real guest-backed smokes for both explicit project_path and bare repo-root auto-detection.

tests/test_workspace_use_case_smokes.py

@@ -436,6 +436,36 @@ class _FakePyro:
         workspace.shells.pop(shell_id, None)
         return {"workspace_id": workspace_id, "shell_id": shell_id, "closed": True}
 
+    def create_server(self, *, profile: str, project_path: Path) -> Any:
+        assert profile == "workspace-core"
+        seed_path = Path(project_path)
+        outer = self
+
+        class _FakeServer:
+            async def call_tool(
+                self,
+                tool_name: str,
+                arguments: dict[str, Any],
+            ) -> tuple[None, dict[str, Any]]:
+                if tool_name != "workspace_create":
+                    raise AssertionError(f"unexpected tool call: {tool_name}")
+                result = outer.create_workspace(
+                    environment=cast(str, arguments["environment"]),
+                    seed_path=seed_path,
+                    name=cast(str | None, arguments.get("name")),
+                    labels=cast(dict[str, str] | None, arguments.get("labels")),
+                )
+                created = outer.status_workspace(cast(str, result["workspace_id"]))
+                created["workspace_seed"] = {
+                    "mode": "directory",
+                    "seed_path": str(seed_path.resolve()),
+                    "origin_kind": "project_path",
+                    "origin_ref": str(seed_path.resolve()),
+                }
+                return None, created
+
+        return _FakeServer()
+
 
 def test_use_case_registry_has_expected_scenarios() -> None:
     expected = (