fix: robust unlink, fail-fast config validation, symlink tests

- uninstall() wraps path.unlink() in try/except OSError to avoid
  partial cleanup on race conditions or permission errors
- setup() raises ValueError on missing config or folder instead of
  silently returning empty
- Added 3 tests: symlink in check_modified, symlink skip/force in
  uninstall (47 total)

src/specify_cli/integrations/base.py

@@ -114,10 +114,15 @@ class IntegrationBase(ABC):
             return created
 
         if not self.config:
-            return created
+            raise ValueError(
+                f"{type(self).__name__}.config is not set; integration "
+                "subclasses must define a non-empty 'config' mapping."
+            )
         folder = self.config.get("folder")
         if not folder:
-            return created
+            raise ValueError(
+                f"{type(self).__name__}.config is missing required 'folder' entry."
+            )
 
         project_root_resolved = project_root.resolve()
         if manifest.project_root != project_root_resolved:

src/specify_cli/integrations/manifest.py

@@ -175,7 +175,11 @@ class IntegrationManifest:
                 if not force and _sha256(path) != expected_hash:
                     skipped.append(path)
                     continue
-            path.unlink()
+            try:
+                path.unlink()
+            except OSError:
+                skipped.append(path)
+                continue
             removed.append(path)
             # Clean up empty parent directories up to project root
             parent = path.parent

tests/test_integrations.py

@@ -233,6 +233,16 @@ class TestManifestCheckModified:
         (tmp_path / "f.txt").unlink()
         assert m.check_modified() == []
 
+    def test_symlink_treated_as_modified(self, tmp_path):
+        """A tracked file replaced with a symlink is reported as modified."""
+        m = IntegrationManifest("test", tmp_path)
+        m.record_file("f.txt", "original")
+        target = tmp_path / "target.txt"
+        target.write_text("target", encoding="utf-8")
+        (tmp_path / "f.txt").unlink()
+        (tmp_path / "f.txt").symlink_to(target)
+        assert m.check_modified() == ["f.txt"]
+
 
 class TestManifestUninstall:
     def test_removes_unmodified(self, tmp_path):
@@ -310,6 +320,36 @@ class TestManifestUninstall:
         assert (tmp_path / "a" / "b" / "other.txt").exists()
         assert (tmp_path / "a" / "b").is_dir()
 
+    def test_symlink_skipped_without_force(self, tmp_path):
+        """A tracked file replaced with a symlink is skipped unless force."""
+        m = IntegrationManifest("test", tmp_path)
+        m.record_file("f.txt", "original")
+        m.save()
+        target = tmp_path / "target.txt"
+        target.write_text("target", encoding="utf-8")
+        (tmp_path / "f.txt").unlink()
+        (tmp_path / "f.txt").symlink_to(target)
+
+        removed, skipped = m.uninstall()
+        assert removed == []
+        assert len(skipped) == 1
+        assert (tmp_path / "f.txt").is_symlink()  # still there
+
+    def test_symlink_removed_with_force(self, tmp_path):
+        """A tracked file replaced with a symlink is removed with force."""
+        m = IntegrationManifest("test", tmp_path)
+        m.record_file("f.txt", "original")
+        m.save()
+        target = tmp_path / "target.txt"
+        target.write_text("target", encoding="utf-8")
+        (tmp_path / "f.txt").unlink()
+        (tmp_path / "f.txt").symlink_to(target)
+
+        removed, skipped = m.uninstall(force=True)
+        assert len(removed) == 1
+        assert not (tmp_path / "f.txt").exists()
+        assert target.exists()  # target not deleted
+
 
 class TestManifestPersistence:
     def test_save_and_load_roundtrip(self, tmp_path):