feat: migrate tags and contributors from TEXT to TEXT[] arrays

Convert tags and contributors columns from comma-separated strings to PostgreSQL
TEXT[] arrays for better data normalization and query performance.

Database Changes:
- schema.sql: Change tags/contributors from TEXT to TEXT[]
- schema.sql: Add GIN indexes for fast array searches
- queries.sql: Update search queries to use ANY() operator
- queries.sql: Update fuzzy search with unnest() for arrays

Generated Code (sqlc):
- models.go: Auto-generated with []string types for tags/contributors
- queries.sql.go: Auto-generated with proper array handling

Handler Changes:
- media.go: Update request structs to use []string for tags/contributors
- media.go: Remove pgtype.Text wrapping, use direct array assignment
- media.go: Add tag normalization in CreateMediaItemHandler
- collections.go: Update tags evaluation to join arrays for comparison
- collections.go: Add strings import for Join() function

Service Changes:
- ebook_scanner.go: Update EbookMetadata struct to use []string
- ebook_scanner.go: Remove string Join(), assign arrays directly
- collection_service.go: Update tags rule evaluation to join arrays
- collection_service.go: Add strings import

New Utilities:
- internal/utils/tags.go: Create NormalizeTags(), JoinTags(), SplitTags()
- Normalizes tags by trimming, lowercasing, removing duplicates/empties

API Documentation:
- bruno/media-items/Create Media Item.bru: Update examples to use arrays
- bruno/media-items/Update Media Item.bru: Update examples to use arrays
- Update docs: tags/contributors now array of string

Breaking Change:
- JSON format changes from "tags": "tag1,tag2" to "tags": ["tag1", "tag2"]
- Tests already use array format (no changes needed)

Benefits:
- GIN indexes enable faster array searches
- Normalization prevents data quality issues (case, duplicates)
- Array operations use PostgreSQL native operators (ANY, &&, unnest)
- Better separation of concerns (no string parsing in application)

internal/database/queries/queries.sql

@@ -363,16 +363,16 @@ WHERE COALESCE(lv.is_visible, true) = true
   AND (
       mi.title ILIKE sqlc.narg('search_pattern') OR 
       mi.author ILIKE sqlc.narg('search_pattern') OR 
-      mi.series ILIKE sqlc.narg('search_pattern') OR
-      mi.tags ILIKE sqlc.narg('search_pattern') OR
-      mi.contributors ILIKE sqlc.narg('search_pattern')
+       mi.series ILIKE sqlc.narg('search_pattern') OR
+       sqlc.narg('search_pattern') = ANY(mi.tags) OR
+       sqlc.narg('search_pattern') = ANY(mi.contributors)
   )
 ORDER BY 
-  CASE 
+   CASE
       WHEN mi.title ILIKE sqlc.narg('search_pattern') THEN 1
       WHEN mi.author ILIKE sqlc.narg('search_pattern') THEN 2
       WHEN mi.series ILIKE sqlc.narg('search_pattern') THEN 3
-      WHEN mi.tags ILIKE sqlc.narg('search_pattern') THEN 4
+      WHEN sqlc.narg('search_pattern') = ANY(mi.tags) THEN 4
       ELSE 5
   END,
   mi.title ASC
@@ -385,23 +385,39 @@ JOIN libraries l ON mi.library_id = l.id
 JOIN library_types lt ON l.library_type_id = lt.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 (
-      word_similarity(sqlc.narg('search_query'), mi.title) > 0.3 OR
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.author, '')) > 0.3 OR
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.series, '')) > 0.3 OR
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.tags, '')) > 0.3 OR
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.contributors, '')) > 0.3
-  )
-ORDER BY 
-  GREATEST(
-      word_similarity(sqlc.narg('search_query'), mi.title),
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.author, '')),
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.series, '')),
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.tags, '')),
-      word_similarity(sqlc.narg('search_query'), COALESCE(mi.contributors, ''))
-  ) DESC,
-  mi.title ASC
-LIMIT sqlc.narg('limit') OFFSET sqlc.narg('offset');
+   AND (
+       word_similarity(sqlc.narg('search_query'), mi.title) > 0.3 OR
+       word_similarity(sqlc.narg('search_query'), COALESCE(mi.author, '')) > 0.3 OR
+       word_similarity(sqlc.narg('search_query'), COALESCE(mi.series, '')) > 0.3 OR
+       EXISTS (
+         SELECT 1 FROM unnest(mi.tags) AS tag
+         WHERE word_similarity(sqlc.narg('search_query'), tag) > 0.3
+         LIMIT 1
+       ) OR
+       EXISTS (
+         SELECT 1 FROM unnest(mi.contributors) AS contributor
+         WHERE word_similarity(sqlc.narg('search_query'), contributor) > 0.3
+         LIMIT 1
+       )
+   )
+ ORDER BY
+   GREATEST(
+       word_similarity(sqlc.narg('search_query'), mi.title),
+       word_similarity(sqlc.narg('search_query'), COALESCE(mi.author, '')),
+       word_similarity(sqlc.narg('search_query'), COALESCE(mi.series, '')),
+       COALESCE(
+         (SELECT MAX(word_similarity(sqlc.narg('search_query'), tag))
+          FROM unnest(mi.tags) AS tag),
+         0
+       ),
+       COALESCE(
+         (SELECT MAX(word_similarity(sqlc.narg('search_query'), contributor))
+          FROM unnest(mi.contributors) AS contributor),
+         0
+       )
+   ) DESC,
+   mi.title ASC
+ LIMIT sqlc.narg('limit') OFFSET sqlc.narg('offset');
 
 -- Media Notes queries
 -- name: CreateMediaNote :one