treewide: better cross-device sync capabilities; in-database storage

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Id99798df6f7e4470caae8a193c2654aa6a6a6964

migrations/postgres/V15__managed_storage.sql

@@ -0,0 +1,30 @@
+-- V15: Managed File Storage
+-- Adds server-side content-addressable storage for uploaded files
+
+-- Add storage mode to media_items (external = file on disk, managed = in content-addressable storage)
+ALTER TABLE media_items ADD COLUMN storage_mode TEXT NOT NULL DEFAULT 'external';
+
+-- Original filename for managed uploads (preserved separately from file_name which may be normalized)
+ALTER TABLE media_items ADD COLUMN original_filename TEXT;
+
+-- When the file was uploaded to managed storage
+ALTER TABLE media_items ADD COLUMN uploaded_at TIMESTAMPTZ;
+
+-- Storage key for looking up the blob (usually same as content_hash for deduplication)
+ALTER TABLE media_items ADD COLUMN storage_key TEXT;
+
+-- Managed blobs table - tracks deduplicated file storage
+CREATE TABLE managed_blobs (
+    content_hash TEXT PRIMARY KEY NOT NULL,
+    file_size BIGINT NOT NULL,
+    mime_type TEXT NOT NULL,
+    reference_count INTEGER NOT NULL DEFAULT 1,
+    stored_at TIMESTAMPTZ NOT NULL,
+    last_verified TIMESTAMPTZ
+);
+
+-- Index for finding managed media items
+CREATE INDEX idx_media_storage_mode ON media_items(storage_mode);
+
+-- Index for finding orphaned blobs (reference_count = 0)
+CREATE INDEX idx_blobs_reference_count ON managed_blobs(reference_count);