fix(db): add 14 missing columns to UpdateMediaItem query

The UpdateMediaItem SQL query only SET 23 of 37 media_items columns,
causing all 3 call sites (admin PUT, bulk update, force rescan) to
silently NULL out the 14 unwired fields on every update.

Added: manga_type, reading_direction, series_count, volume, imprint,
age_rating, web_url, metadata_notes, community_rating, story_arc,
is_black_and_white, alternate_info, scan_information, summary.

Regenerated sqlc Go code (queries.sql.go) with 37-param
UpdateMediaItemParams struct.

internal/database/queries/queries.sql

@@ -249,6 +249,20 @@ UPDATE media_items SET
     goodreads_id = $21,
     openlibrary_id = $22,
     google_books_id = $23,
+    manga_type = $24,
+    reading_direction = $25,
+    series_count = $26,
+    volume = $27,
+    imprint = $28,
+    age_rating = $29,
+    web_url = $30,
+    metadata_notes = $31,
+    community_rating = $32,
+    story_arc = $33,
+    is_black_and_white = $34,
+    alternate_info = $35,
+    scan_information = $36,
+    summary = $37,
     updated_at = NOW()
 WHERE id = $1
 RETURNING *;