feat(storage): add delete_href method to remove files and clean up empty directories

chore(docker): remove MongoDB service and related configurations from local setup

feat(migrations): create ChapterMeta table and add search_name, size_bytes, mtime_epoch, lastScannedAt, review_status, and review_payload columns to SourceAsset

chore(dependencies): remove motor and pymongo from project dependencies

migrations/2026_05_add_chapter_meta.sql

@@ -0,0 +1,11 @@
+CREATE TABLE IF NOT EXISTS "ChapterMeta" (
+    id TEXT PRIMARY KEY,
+    "novelId" TEXT NOT NULL,
+    number INT NOT NULL,
+    title TEXT,
+    views INT NOT NULL DEFAULT 0,
+    "createdAt" TIMESTAMPTZ,
+    UNIQUE("novelId", number)
+);
+
+CREATE INDEX IF NOT EXISTS "ChapterMeta_novel_number_idx" ON "ChapterMeta"("novelId", number);