test: add comprehensive tests for config profile git mounts

- Add git mount merge function tests
- Add profile resolution tests with git mounts
- Add integration tests for CRUD with git mounts
- Add glob expansion tests (patterns, limits, repo boundary)
- Add branch checkout tests (success and failure)
- Add error handling tests for missing repos/invalid UUIDs

All 52 tests pass.

apps/api/tests/unit/test_config_profile_resolver.py

@@ -13,6 +13,7 @@ from src.services.config_profile_resolver import (
     _merge_files,
     _merge_mounts,
     _merge_runtime_hints,
+    _merge_git_mounts,
 )
 
 
@@ -97,6 +98,39 @@ class TestMergeFunctions:
         assert result["/app"].mode == "ro"
         assert overrides == {"/app": "source"}
 
+    def test_merge_git_mounts_basic(self) -> None:
+        """Test basic git mount merging."""
+        result = _merge_git_mounts(
+            [],
+            [{"repo_id": "repo1", "source_path": ".", "target_path": "/app"}],
+            "source",
+        )
+        assert len(result) == 1
+        assert result[0]["repo_id"] == "repo1"
+        assert result[0]["target_path"] == "/app"
+
+    def test_merge_git_mounts_override_same_repo_target(self) -> None:
+        """Test that git mounts with same repo+target override."""
+        result = _merge_git_mounts(
+            [{"repo_id": "repo1", "source_path": ".", "target_path": "/app", "branch": "main"}],
+            [{"repo_id": "repo1", "source_path": "src", "target_path": "/app", "branch": "dev"}],
+            "source",
+        )
+        assert len(result) == 1
+        assert result[0]["source_path"] == "src"
+        assert result[0]["branch"] == "dev"
+
+    def test_merge_git_mounts_different_targets(self) -> None:
+        """Test that git mounts with different targets are preserved."""
+        result = _merge_git_mounts(
+            [{"repo_id": "repo1", "source_path": ".", "target_path": "/app"}],
+            [{"repo_id": "repo2", "source_path": ".", "target_path": "/config"}],
+            "source",
+        )
+        assert len(result) == 2
+        targets = {m["target_path"] for m in result}
+        assert targets == {"/app", "/config"}
+
 
 class TestResolveProfile:
     """Unit tests for profile resolution."""
@@ -250,6 +284,76 @@ class TestResolveProfile:
         with pytest.raises(ConfigProfileCycleError):
             await resolve_profile(db_session, profile_a.id)
 
+    @pytest.mark.asyncio
+    async def test_resolve_profile_with_git_mounts(self, db_session: AsyncSession) -> None:
+        """Test resolving a profile with git mounts."""
+        user_id = uuid.uuid4()
+        
+        profile = ConfigProfile(
+            id=uuid.uuid4(),
+            user_id=user_id,
+            name="with-git-mounts",
+            env_vars={},
+            files={},
+            git_mounts=[
+                {"repo_id": "repo1", "source_path": ".", "target_path": "/app"},
+            ],
+        )
+        db_session.add(profile)
+        await db_session.commit()
+        
+        result = await resolve_profile(db_session, profile.id)
+        assert len(result.git_mounts) == 1
+        assert result.git_mounts[0]["repo_id"] == "repo1"
+        assert result.git_mounts[0]["target_path"] == "/app"
+    
+    @pytest.mark.asyncio
+    async def test_resolve_profile_with_git_mount_includes(self, db_session: AsyncSession) -> None:
+        """Test resolving a profile that includes another with git mounts."""
+        user_id = uuid.uuid4()
+        
+        # Create base profile with git mount
+        base = ConfigProfile(
+            id=uuid.uuid4(),
+            user_id=user_id,
+            name="base",
+            env_vars={},
+            files={},
+            git_mounts=[
+                {"repo_id": "repo1", "source_path": ".", "target_path": "/app"},
+            ],
+        )
+        db_session.add(base)
+        
+        # Create child profile with its own git mount
+        child = ConfigProfile(
+            id=uuid.uuid4(),
+            user_id=user_id,
+            name="child",
+            env_vars={},
+            files={},
+            git_mounts=[
+                {"repo_id": "repo2", "source_path": "config", "target_path": "/config"},
+            ],
+        )
+        db_session.add(child)
+        await db_session.commit()
+        
+        # Create include relationship
+        include = ConfigProfileInclude(
+            id=uuid.uuid4(),
+            profile_id=child.id,
+            included_profile_id=base.id,
+            order_index=0,
+        )
+        db_session.add(include)
+        await db_session.commit()
+        
+        result = await resolve_profile(db_session, child.id)
+        assert len(result.git_mounts) == 2
+        targets = {m["target_path"] for m in result.git_mounts}
+        assert targets == {"/app", "/config"}
+
     @pytest.mark.asyncio
     async def test_resolve_profile_not_found(self, db_session: AsyncSession) -> None:
         """Test resolving a non-existent profile."""