feat: multi-library foundation (schema + libraries module)

Adds a `libraries` registry table and threads library_id through
per-instance metadata tables (image_exif, photo_insights,
entity_photo_links, video_preview_clips). File-path columns renamed to
rel_path to make the relative-to-root semantics explicit. Adds
content_hash + size_bytes on image_exif to support future hash-keyed
thumbnail/HLS dedup. Tags and favorites stay library-agnostic so they
share across libraries by rel_path.

Behavior is unchanged: a single primary library (id=1) is seeded from
BASE_PATH on first boot; all handlers and DAOs route through it as a
transitional shim until the API gains a library query param.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

migrations/2026-04-17-000000_multi_library/down.sql

@@ -0,0 +1,155 @@
+-- Revert multi-library support.
+-- Drops library_id/content_hash/size_bytes, renames rel_path back to the
+-- original column names, and drops the libraries table. Rows originally
+-- from non-primary libraries (id > 1) would be orphaned, so the rollback
+-- keeps only rows from library_id=1.
+
+PRAGMA foreign_keys=OFF;
+
+-- tagged_photo: rel_path → photo_name.
+DROP INDEX IF EXISTS idx_tagged_photo_relpath_tag;
+DROP INDEX IF EXISTS idx_tagged_photo_rel_path;
+ALTER TABLE tagged_photo RENAME COLUMN rel_path TO photo_name;
+CREATE INDEX IF NOT EXISTS idx_tagged_photo_photo_name ON tagged_photo(photo_name);
+CREATE INDEX IF NOT EXISTS idx_tagged_photo_count ON tagged_photo(photo_name, tag_id);
+
+-- favorites: rel_path → path.
+DROP INDEX IF EXISTS idx_favorites_unique;
+DROP INDEX IF EXISTS idx_favorites_rel_path;
+ALTER TABLE favorites RENAME COLUMN rel_path TO path;
+CREATE INDEX IF NOT EXISTS idx_favorites_path ON favorites(path);
+CREATE UNIQUE INDEX IF NOT EXISTS idx_favorites_unique ON favorites(userid, path);
+
+-- video_preview_clips: drop library_id, rel_path → file_path.
+CREATE TABLE video_preview_clips_old (
+    id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+    file_path TEXT NOT NULL UNIQUE,
+    status TEXT NOT NULL DEFAULT 'pending',
+    duration_seconds REAL,
+    file_size_bytes INTEGER,
+    error_message TEXT,
+    created_at TEXT NOT NULL,
+    updated_at TEXT NOT NULL
+);
+
+INSERT INTO video_preview_clips_old (
+    id, file_path, status, duration_seconds, file_size_bytes,
+    error_message, created_at, updated_at
+)
+SELECT
+    id, rel_path, status, duration_seconds, file_size_bytes,
+    error_message, created_at, updated_at
+FROM video_preview_clips
+WHERE library_id = 1;
+
+DROP TABLE video_preview_clips;
+ALTER TABLE video_preview_clips_old RENAME TO video_preview_clips;
+
+CREATE INDEX idx_preview_clips_file_path ON video_preview_clips(file_path);
+CREATE INDEX idx_preview_clips_status    ON video_preview_clips(status);
+
+-- entity_photo_links: drop library_id, rel_path → file_path.
+CREATE TABLE entity_photo_links_old (
+    id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+    entity_id INTEGER NOT NULL,
+    file_path TEXT NOT NULL,
+    role TEXT NOT NULL,
+    CONSTRAINT fk_epl_entity FOREIGN KEY (entity_id) REFERENCES entities(id) ON DELETE CASCADE,
+    UNIQUE(entity_id, file_path, role)
+);
+
+INSERT INTO entity_photo_links_old (id, entity_id, file_path, role)
+SELECT id, entity_id, rel_path, role
+FROM entity_photo_links
+WHERE library_id = 1;
+
+DROP TABLE entity_photo_links;
+ALTER TABLE entity_photo_links_old RENAME TO entity_photo_links;
+
+CREATE INDEX idx_entity_photo_links_entity ON entity_photo_links(entity_id);
+CREATE INDEX idx_entity_photo_links_photo  ON entity_photo_links(file_path);
+
+-- photo_insights: drop library_id, rel_path → file_path.
+CREATE TABLE photo_insights_old (
+    id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
+    file_path TEXT NOT NULL,
+    title TEXT NOT NULL,
+    summary TEXT NOT NULL,
+    generated_at BIGINT NOT NULL,
+    model_version TEXT NOT NULL,
+    is_current BOOLEAN NOT NULL DEFAULT 0,
+    training_messages TEXT,
+    approved BOOLEAN
+);
+
+INSERT INTO photo_insights_old (
+    id, file_path, title, summary, generated_at, model_version, is_current,
+    training_messages, approved
+)
+SELECT
+    id, rel_path, title, summary, generated_at, model_version, is_current,
+    training_messages, approved
+FROM photo_insights
+WHERE library_id = 1;
+
+DROP TABLE photo_insights;
+ALTER TABLE photo_insights_old RENAME TO photo_insights;
+
+CREATE INDEX idx_photo_insights_file_path ON photo_insights(file_path);
+CREATE INDEX idx_photo_insights_current   ON photo_insights(file_path, is_current);
+
+-- image_exif: drop library_id/content_hash/size_bytes, rel_path → file_path.
+CREATE TABLE image_exif_old (
+    id INTEGER PRIMARY KEY NOT NULL,
+    file_path TEXT NOT NULL UNIQUE,
+    camera_make TEXT,
+    camera_model TEXT,
+    lens_model TEXT,
+    width INTEGER,
+    height INTEGER,
+    orientation INTEGER,
+    gps_latitude REAL,
+    gps_longitude REAL,
+    gps_altitude REAL,
+    focal_length REAL,
+    aperture REAL,
+    shutter_speed TEXT,
+    iso INTEGER,
+    date_taken BIGINT,
+    created_time BIGINT NOT NULL,
+    last_modified BIGINT NOT NULL
+);
+
+INSERT INTO image_exif_old (
+    id, file_path,
+    camera_make, camera_model, lens_model,
+    width, height, orientation,
+    gps_latitude, gps_longitude, gps_altitude,
+    focal_length, aperture, shutter_speed, iso, date_taken,
+    created_time, last_modified
+)
+SELECT
+    id, rel_path,
+    camera_make, camera_model, lens_model,
+    width, height, orientation,
+    gps_latitude, gps_longitude, gps_altitude,
+    focal_length, aperture, shutter_speed, iso, date_taken,
+    created_time, last_modified
+FROM image_exif
+WHERE library_id = 1;
+
+DROP TABLE image_exif;
+ALTER TABLE image_exif_old RENAME TO image_exif;
+
+CREATE INDEX idx_image_exif_file_path  ON image_exif(file_path);
+CREATE INDEX idx_image_exif_camera     ON image_exif(camera_make, camera_model);
+CREATE INDEX idx_image_exif_gps        ON image_exif(gps_latitude, gps_longitude);
+CREATE INDEX idx_image_exif_date_taken ON image_exif(date_taken);
+CREATE INDEX idx_image_exif_date_path  ON image_exif(date_taken DESC, file_path);
+
+-- Finally, drop the libraries registry.
+DROP TABLE libraries;
+
+PRAGMA foreign_keys=ON;
+
+ANALYZE;