feat: add fuzzy tags_filter to search query

- Add tags_filter parameter to SearchMediaItemsUnified
- Add EXISTS clause with word_similarity() for fuzzy tag matching
- Add tag similarity scoring to ORDER BY clause (GREATEST function)
- Add SearchTagsValues query for autocomplete with ::TEXT cast
- Keep genre_filter for backward compatibility
- Regenerate Go code with sqlc generate

This enables filtering books by tags (from Calibre) instead of genre,
which is always NULL for imported books. Uses fuzzy matching consistent
with author/series filters, with best matches sorted first.

Relates to IMPLEMENTATION_TAGS_FILTER.md Phase 1

internal/database/querier.go

@@ -290,6 +290,7 @@ type Querier interface {
 	SearchMediaItems(ctx context.Context, arg SearchMediaItemsParams) ([]SearchMediaItemsRow, error)
 	SearchMediaItemsUnified(ctx context.Context, arg SearchMediaItemsUnifiedParams) ([]SearchMediaItemsUnifiedRow, error)
 	SearchSeriesValues(ctx context.Context, arg SearchSeriesValuesParams) ([]SearchSeriesValuesRow, error)
+	SearchTagsValues(ctx context.Context, arg SearchTagsValuesParams) ([]SearchTagsValuesRow, error)
 	// Library Visibility queries
 	SetLibraryVisibility(ctx context.Context, arg SetLibraryVisibilityParams) (LibraryVisibility, error)
 	// Set system config

internal/database/queries.sql.go

@@ -7254,92 +7254,99 @@ WHERE COALESCE(lv.is_visible, true) = true
   AND ($5 = '' OR word_similarity($5, COALESCE(mi.genre, '')) > 0.3)
   -- Fuzzy language filter
   AND ($6 = '' OR word_similarity($6, COALESCE(mi.language, '')) > 0.3)
+  -- Tags filter (NEW - fuzzy match against tags array)
+  AND ($7 = '' OR EXISTS (
+    SELECT 1 FROM unnest(mi.tags_search) AS tag
+    WHERE word_similarity($7, tag) > 0.3
+  ))
   -- Year range (exact)
-  AND ($7 = 0 OR mi.copyright_year >= $7)
+  AND ($8 = 0 OR mi.copyright_year >= $8)
-  AND ($8 = 0 OR mi.copyright_year <= $8)
+  AND ($9 = 0 OR mi.copyright_year <= $9)
   -- Boolean (exact)
-  AND ($9 = false OR mi.cover_image_path IS NOT NULL)
+  AND ($10 = false OR mi.cover_image_path IS NOT NULL)
   -- Search query (fuzzy or exact based on quotes)
   AND (
-    $10 = '' OR
+    $11 = '' OR
     -- Fuzzy search (default)
-    $11 = false AND (
+    $12 = false AND (
-      word_similarity($10, mi.title) > 0.3 OR
+      word_similarity($11, mi.title) > 0.3 OR
-      word_similarity($10, COALESCE(mi.author, '')) > 0.3 OR
+      word_similarity($11, COALESCE(mi.author, '')) > 0.3 OR
-      word_similarity($10, COALESCE(mi.series, '')) > 0.3 OR
+      word_similarity($11, COALESCE(mi.series, '')) > 0.3 OR
       EXISTS (
         SELECT 1 FROM unnest(mi.tags_search) AS tag
-        WHERE word_similarity($10, tag) > 0.3
+        WHERE word_similarity($11, tag) > 0.3
         LIMIT 1
       ) OR
       EXISTS (
         SELECT 1 FROM unnest(mi.contributors_search) AS contributor
-        WHERE word_similarity($10, contributor) > 0.3
+        WHERE word_similarity($11, contributor) > 0.3
         LIMIT 1
       )
     ) OR
     -- Exact search (with quotes)
-    $11 = true AND (
+    $12 = true AND (
-      mi.title ILIKE $12 OR
+      mi.title ILIKE $13 OR
-      mi.author ILIKE $12 OR
+      mi.author ILIKE $13 OR
-      mi.series ILIKE $12 OR
+      mi.series ILIKE $13 OR
-      $12 = ANY(mi.tags_search) OR
+      $13 = ANY(mi.tags_search) OR
-      $12 = ANY(mi.contributors_search)
+      $13 = ANY(mi.contributors_search)
     )
   )
 ORDER BY
   mi.id,
   -- Primary sort: relevance score when searching
   CASE
-    WHEN $10 != '' THEN
+    WHEN $11 != '' THEN
       GREATEST(
-        CASE WHEN $11 = false THEN
+        CASE WHEN $12 = false THEN
-          word_similarity($10, mi.title)
+          word_similarity($11, mi.title)
         ELSE 0 END,
-        CASE WHEN $11 = false THEN
+        CASE WHEN $12 = false THEN
-          word_similarity($10, COALESCE(mi.author, ''))
+          word_similarity($11, COALESCE(mi.author, ''))
         ELSE 0 END,
         word_similarity($3, COALESCE(mi.author, '')),
-        word_similarity($5, COALESCE(mi.genre, ''))
+        word_similarity($5, COALESCE(mi.genre, '')),
+        (SELECT MAX(word_similarity($7, tag))
+         FROM unnest(mi.tags_search) AS tag)
       )
     ELSE 0
   END DESC,
   -- Secondary sort: user-specified sort parameter
   CASE
-    WHEN $13 = 'title ASC' THEN mi.title
+    WHEN $14 = 'title ASC' THEN mi.title
     ELSE ''
   END ASC,
   CASE
-    WHEN $13 = 'title DESC' THEN mi.title
+    WHEN $14 = 'title DESC' THEN mi.title
     ELSE ''
   END DESC,
   CASE
-    WHEN $13 = 'author ASC' THEN COALESCE(mi.author, '')
+    WHEN $14 = 'author ASC' THEN COALESCE(mi.author, '')
     ELSE ''
   END ASC,
   CASE
-    WHEN $13 = 'author DESC' THEN COALESCE(mi.author, '')
+    WHEN $14 = 'author DESC' THEN COALESCE(mi.author, '')
     ELSE ''
   END DESC,
   CASE
-    WHEN $13 = 'created_at ASC' THEN mi.created_at
+    WHEN $14 = 'created_at ASC' THEN mi.created_at
     ELSE '1970-01-01'::timestamp
   END ASC,
   CASE
-    WHEN $13 = 'created_at DESC' THEN mi.created_at
+    WHEN $14 = 'created_at DESC' THEN mi.created_at
     ELSE '1970-01-01'::timestamp
   END DESC,
   CASE
-    WHEN $13 = 'page_count ASC' THEN COALESCE(mi.page_count::text, '0')
+    WHEN $14 = 'page_count ASC' THEN COALESCE(mi.page_count::text, '0')
     ELSE ''
   END ASC,
   CASE
-    WHEN $13 = 'page_count DESC' THEN COALESCE(mi.page_count::text, '0')
+    WHEN $14 = 'page_count DESC' THEN COALESCE(mi.page_count::text, '0')
     ELSE ''
   END DESC,
   -- Tertiary sort: title (default fallback)
   mi.title ASC
-LIMIT $15 OFFSET $14
+LIMIT $16 OFFSET $15
 `
 
 type SearchMediaItemsUnifiedParams struct {
@@ -7349,6 +7356,7 @@ type SearchMediaItemsUnifiedParams struct {
 	SeriesFilter   interface{} `db:"series_filter" json:"series_filter"`
 	GenreFilter    interface{} `db:"genre_filter" json:"genre_filter"`
 	LanguageFilter interface{} `db:"language_filter" json:"language_filter"`
+	TagsFilter     interface{} `db:"tags_filter" json:"tags_filter"`
 	YearMin        interface{} `db:"year_min" json:"year_min"`
 	YearMax        interface{} `db:"year_max" json:"year_max"`
 	HasCover       interface{} `db:"has_cover" json:"has_cover"`
@@ -7417,6 +7425,7 @@ func (q *Queries) SearchMediaItemsUnified(ctx context.Context, arg SearchMediaIt
 		arg.SeriesFilter,
 		arg.GenreFilter,
 		arg.LanguageFilter,
+		arg.TagsFilter,
 		arg.YearMin,
 		arg.YearMax,
 		arg.HasCover,
@@ -7550,6 +7559,63 @@ func (q *Queries) SearchSeriesValues(ctx context.Context, arg SearchSeriesValues
 	return items, nil
 }
 
+const SearchTagsValues = `-- name: SearchTagsValues :many
+SELECT
+  unnest(mi.tags_search)::TEXT as value,
+  COUNT(*) as count,
+  word_similarity($1, unnest(mi.tags_search))::float8 as score
+FROM media_items mi
+JOIN libraries l ON mi.library_id = l.id
+LEFT JOIN library_visibility lv ON l.id = lv.library_id AND lv.user_id = $2
+WHERE COALESCE(lv.is_visible, true) = true
+  AND ($3::uuid IS NULL OR mi.library_id = $3::uuid)
+  AND unnest(mi.tags_search) IS NOT NULL
+  AND word_similarity($1, unnest(mi.tags_search)) > 0.3
+GROUP BY unnest(mi.tags_search), word_similarity($1, unnest(mi.tags_search))::float8
+ORDER BY word_similarity($1, unnest(mi.tags_search))::float8 DESC, COUNT DESC
+LIMIT $5 OFFSET $4
+`
+
+type SearchTagsValuesParams struct {
+	SearchQuery pgtype.Text `db:"search_query" json:"search_query"`
+	UserID      pgtype.UUID `db:"user_id" json:"user_id"`
+	LibraryID   pgtype.UUID `db:"library_id" json:"library_id"`
+	Offset      pgtype.Int4 `db:"offset" json:"offset"`
+	Limit       pgtype.Int4 `db:"limit" json:"limit"`
+}
+
+type SearchTagsValuesRow struct {
+	Value string  `db:"value" json:"value"`
+	Count int64   `db:"count" json:"count"`
+	Score float64 `db:"score" json:"score"`
+}
+
+func (q *Queries) SearchTagsValues(ctx context.Context, arg SearchTagsValuesParams) ([]SearchTagsValuesRow, error) {
+	rows, err := q.db.Query(ctx, SearchTagsValues,
+		arg.SearchQuery,
+		arg.UserID,
+		arg.LibraryID,
+		arg.Offset,
+		arg.Limit,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	items := []SearchTagsValuesRow{}
+	for rows.Next() {
+		var i SearchTagsValuesRow
+		if err := rows.Scan(&i.Value, &i.Count, &i.Score); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const SetLibraryVisibility = `-- name: SetLibraryVisibility :one
 INSERT INTO library_visibility (user_id, library_id, is_visible)
 VALUES ($1, $2, $3)

internal/database/queries/queries.sql

@@ -435,6 +435,11 @@ WHERE COALESCE(lv.is_visible, true) = true
   AND (sqlc.narg('genre_filter') = '' OR word_similarity(sqlc.narg('genre_filter'), COALESCE(mi.genre, '')) > 0.3)
   -- Fuzzy language filter
   AND (sqlc.narg('language_filter') = '' OR word_similarity(sqlc.narg('language_filter'), COALESCE(mi.language, '')) > 0.3)
+  -- Tags filter (NEW - fuzzy match against tags array)
+  AND (sqlc.narg('tags_filter') = '' OR EXISTS (
+    SELECT 1 FROM unnest(mi.tags_search) AS tag
+    WHERE word_similarity(sqlc.narg('tags_filter'), tag) > 0.3
+  ))
   -- Year range (exact)
   AND (sqlc.narg('year_min') = 0 OR mi.copyright_year >= sqlc.narg('year_min'))
   AND (sqlc.narg('year_max') = 0 OR mi.copyright_year <= sqlc.narg('year_max'))
@@ -481,7 +486,9 @@ ORDER BY
           word_similarity(sqlc.narg('search_query'), COALESCE(mi.author, ''))
         ELSE 0 END,
         word_similarity(sqlc.narg('author_filter'), COALESCE(mi.author, '')),
-        word_similarity(sqlc.narg('genre_filter'), COALESCE(mi.genre, ''))
+        word_similarity(sqlc.narg('genre_filter'), COALESCE(mi.genre, '')),
+        (SELECT MAX(word_similarity(sqlc.narg('tags_filter'), tag))
+         FROM unnest(mi.tags_search) AS tag)
       )
     ELSE 0
   END DESC,
@@ -556,6 +563,22 @@ GROUP BY mi.genre, word_similarity(sqlc.narg('search_query'), COALESCE(mi.genre,
 ORDER BY score DESC, count DESC
 LIMIT sqlc.narg('limit') OFFSET sqlc.narg('offset');
 
+-- name: SearchTagsValues :many
+SELECT
+  unnest(mi.tags_search)::TEXT as value,
+  COUNT(*) as count,
+  word_similarity(sqlc.narg('search_query'), unnest(mi.tags_search))::float8 as score
+FROM media_items mi
+JOIN libraries l ON mi.library_id = l.id
+LEFT JOIN library_visibility lv ON l.id = lv.library_id AND lv.user_id = sqlc.narg('user_id')
+WHERE COALESCE(lv.is_visible, true) = true
+  AND (sqlc.narg('library_id')::uuid IS NULL OR mi.library_id = sqlc.narg('library_id')::uuid)
+  AND unnest(mi.tags_search) IS NOT NULL
+  AND word_similarity(sqlc.narg('search_query'), unnest(mi.tags_search)) > 0.3
+GROUP BY unnest(mi.tags_search), word_similarity(sqlc.narg('search_query'), unnest(mi.tags_search))::float8
+ORDER BY word_similarity(sqlc.narg('search_query'), unnest(mi.tags_search))::float8 DESC, COUNT DESC
+LIMIT sqlc.narg('limit') OFFSET sqlc.narg('offset');
+
 -- name: SearchSeriesValues :many
 SELECT
   mi.series as value,