feat: add live config profile refresh

- Standardize built-in tool users for shared writable profile mounts
- Mount canonical non-Git profile sources across compatible instances
- Report restart-required outcomes and guard active profile deletion
- Surface restart feedback in config profile editing

Quality gates: frontend build passed; backend py_compile and LSP passed.
Skipped: backend pytest/Ruff unavailable; Docker/manual checks not approved.

apps/api/tests/unit/test_config_profile_resolver.py

@@ -532,6 +532,54 @@ class TestApplyResolvedProfile:
         assert Path(volumes[0]["source"]).name == "workspace_x_y"
         assert (Path(volumes[0]["source"]) / "z.json").exists()
 
+    def test_top_level_files_use_profile_scoped_direct_bind_mounts(self, tmp_path) -> None:
+        """Top-level files are shared safely without mounting over a workspace."""
+        profile_id = uuid.uuid4()
+        resolved = ResolvedProfile(
+            profile_id=profile_id,
+            profile_name="test",
+            files={".tool/config.toml": "setting = true"},
+        )
+
+        instance_root = tmp_path / "instances"
+        _, files, volumes, _ = apply_resolved_profile(
+            str(instance_root / "instance-a"),
+            resolved,
+            working_dir="/workspace/project",
+        )
+
+        canonical_file = (
+            instance_root / "config-profiles" / str(profile_id) / "files" / ".tool" / "config.toml"
+        )
+        assert files == {}
+        assert volumes == [
+            {
+                "source": str(canonical_file),
+                "target": "/workspace/project/.tool/config.toml",
+                "type": "bind",
+                "readonly": False,
+            }
+        ]
+        assert canonical_file.read_text() == "setting = true"
+
+    def test_instances_share_profile_scoped_mount_sources(self, tmp_path) -> None:
+        """Different instance paths resolve a profile to one canonical source."""
+        profile_id = uuid.uuid4()
+        resolved = ResolvedProfile(
+            profile_id=profile_id,
+            profile_name="test",
+            mounts={"/app": ResolvedMount(target="/app", mode="rw", files={"config.ini": "x"})},
+        )
+
+        instance_root = tmp_path / "instances"
+        _, _, first_volumes, _ = apply_resolved_profile(str(instance_root / "instance-a"), resolved)
+        _, _, second_volumes, _ = apply_resolved_profile(str(instance_root / "instance-b"), resolved)
+
+        assert first_volumes[0]["source"] == second_volumes[0]["source"]
+        assert first_volumes[0]["source"] == str(
+            instance_root / "config-profiles" / str(profile_id) / "mounts" / "app"
+        )
+
     def test_empty_mount_produces_no_volumes(self, tmp_path) -> None:
         """A mount with no files should not produce any volume entries."""
         resolved = ResolvedProfile(
@@ -579,7 +627,7 @@ class TestApplyResolvedProfile:
 
         assert len(volumes) == 1
         assert volumes[0]["target"] == "/etc/app"
-        assert volumes[0].get("readonly") is True
+        assert volumes[0].get("readonly")
 
     def test_writable_mount_does_not_set_readonly_flag(self, tmp_path) -> None:
         """A mount with mode 'rw' should not set readonly on the volume entry."""
@@ -598,7 +646,7 @@ class TestApplyResolvedProfile:
 
         assert len(volumes) == 1
         assert volumes[0]["target"] == "/app"
-        assert volumes[0].get("readonly") is False
+        assert not volumes[0].get("readonly")
 
 
 class TestCheckIncludeCycle: