feat: add anime metadata editing and NFO diagnostics

- Add PUT /anime/{key} endpoint for updating anime key, tmdb_id, tvdb_id
- Add NFO diagnostics and repair endpoints (GET/POST /nfo/diagnostics)
- Add edit modal UI with context menu integration
- Add frontend JS modules for context-menu and edit-modal
- Add comprehensive tests for edit, rename, and NFO repair flows

tests/unit/test_anime_key_rename.py

@@ -0,0 +1,161 @@
+"""Unit tests for anime key rename logic and validation."""
+import pytest
+from pydantic import ValidationError
+
+from src.server.models.anime import AnimeMetadataUpdate, KEY_PATTERN
+
+
+class TestKeyValidation:
+    """Tests for AnimeMetadataUpdate key validation."""
+
+    def test_valid_key_simple(self):
+        """Test simple valid key."""
+        model = AnimeMetadataUpdate(key="attack-on-titan")
+        assert model.key == "attack-on-titan"
+
+    def test_valid_key_single_char(self):
+        """Test single character key is valid."""
+        model = AnimeMetadataUpdate(key="a")
+        assert model.key == "a"
+
+    def test_valid_key_numbers(self):
+        """Test key with numbers."""
+        model = AnimeMetadataUpdate(key="86-eighty-six")
+        assert model.key == "86-eighty-six"
+
+    def test_valid_key_allows_hyphens(self):
+        """Test hyphens in key are allowed."""
+        model = AnimeMetadataUpdate(key="my-anime-key")
+        assert model.key == "my-anime-key"
+
+    def test_valid_key_normalizes_to_lowercase(self):
+        """Test key is normalized to lowercase."""
+        model = AnimeMetadataUpdate(key="Attack-On-Titan")
+        assert model.key == "attack-on-titan"
+
+    def test_valid_key_strips_whitespace(self):
+        """Test key strips leading/trailing whitespace."""
+        model = AnimeMetadataUpdate(key="  my-key  ")
+        assert model.key == "my-key"
+
+    def test_invalid_key_spaces(self):
+        """Test key with spaces is rejected."""
+        with pytest.raises(ValidationError) as exc_info:
+            AnimeMetadataUpdate(key="my anime key")
+        assert "Key must contain only" in str(exc_info.value)
+
+    def test_invalid_key_uppercase_special(self):
+        """Test key with special characters is rejected."""
+        with pytest.raises(ValidationError) as exc_info:
+            AnimeMetadataUpdate(key="anime!@#key")
+        assert "Key must contain only" in str(exc_info.value)
+
+    def test_invalid_key_empty(self):
+        """Test empty key is rejected."""
+        with pytest.raises(ValidationError) as exc_info:
+            AnimeMetadataUpdate(key="")
+        assert "cannot be empty" in str(exc_info.value)
+
+    def test_invalid_key_only_whitespace(self):
+        """Test whitespace-only key is rejected."""
+        with pytest.raises(ValidationError) as exc_info:
+            AnimeMetadataUpdate(key="   ")
+        assert "cannot be empty" in str(exc_info.value)
+
+    def test_invalid_key_starts_with_hyphen(self):
+        """Test key starting with hyphen is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(key="-my-key")
+
+    def test_invalid_key_ends_with_hyphen(self):
+        """Test key ending with hyphen is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(key="my-key-")
+
+    def test_key_none_is_allowed(self):
+        """Test None key (no change requested) is allowed."""
+        model = AnimeMetadataUpdate(key=None)
+        assert model.key is None
+
+    def test_key_omitted_is_allowed(self):
+        """Test omitting key entirely is allowed."""
+        model = AnimeMetadataUpdate(tmdb_id=1234)
+        assert model.key is None
+
+
+class TestTmdbIdValidation:
+    """Tests for tmdb_id validation."""
+
+    def test_valid_tmdb_id(self):
+        """Test valid positive TMDB ID."""
+        model = AnimeMetadataUpdate(tmdb_id=1429)
+        assert model.tmdb_id == 1429
+
+    def test_tmdb_id_none(self):
+        """Test None tmdb_id is allowed."""
+        model = AnimeMetadataUpdate(tmdb_id=None)
+        assert model.tmdb_id is None
+
+    def test_tmdb_id_negative_rejected(self):
+        """Test negative tmdb_id is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(tmdb_id=-1)
+
+    def test_tmdb_id_zero_rejected(self):
+        """Test zero tmdb_id is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(tmdb_id=0)
+
+
+class TestTvdbIdValidation:
+    """Tests for tvdb_id validation."""
+
+    def test_valid_tvdb_id(self):
+        """Test valid positive TVDB ID."""
+        model = AnimeMetadataUpdate(tvdb_id=267440)
+        assert model.tvdb_id == 267440
+
+    def test_tvdb_id_none(self):
+        """Test None tvdb_id is allowed."""
+        model = AnimeMetadataUpdate(tvdb_id=None)
+        assert model.tvdb_id is None
+
+    def test_tvdb_id_negative_rejected(self):
+        """Test negative tvdb_id is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(tvdb_id=-5)
+
+    def test_tvdb_id_zero_rejected(self):
+        """Test zero tvdb_id is rejected."""
+        with pytest.raises(ValidationError):
+            AnimeMetadataUpdate(tvdb_id=0)
+
+
+class TestKeyPattern:
+    """Tests for the KEY_PATTERN regex directly."""
+
+    @pytest.mark.parametrize("key", [
+        "a",
+        "abc",
+        "attack-on-titan",
+        "86-eighty-six",
+        "a1b2c3",
+        "x",
+        "1",
+    ])
+    def test_valid_patterns(self, key):
+        """Test keys that should match the pattern."""
+        assert KEY_PATTERN.match(key) is not None
+
+    @pytest.mark.parametrize("key", [
+        "-start",
+        "end-",
+        "has space",
+        "UPPER",
+        "special!char",
+        "under_score",
+        "",
+    ])
+    def test_invalid_patterns(self, key):
+        """Test keys that should not match the pattern."""
+        assert KEY_PATTERN.match(key) is None