feat(backend): add standalone data plane

Replace the Supabase application data plane with the Node/PostgreSQL API, migrate mobile, admin, web, and MCP callers, add controlled cutover tooling, and define hardened Dokploy infrastructure.

apps/api/drizzle/0006_media_storage.sql

@@ -0,0 +1,35 @@
+CREATE TABLE IF NOT EXISTS media_objects (
+  id uuid PRIMARY KEY,
+  owner_id uuid NOT NULL REFERENCES profiles(id) ON DELETE CASCADE,
+  couple_id uuid REFERENCES couples(id) ON DELETE CASCADE,
+  kind text NOT NULL CHECK (kind IN ('avatar', 'response', 'chat', 'feedback')),
+  storage_key text NOT NULL UNIQUE,
+  mime_type text NOT NULL,
+  byte_size integer NOT NULL CHECK (byte_size > 0),
+  question_id uuid REFERENCES questions(id) ON DELETE CASCADE,
+  match_id uuid REFERENCES matches(id) ON DELETE CASCADE,
+  expires_at timestamptz,
+  created_at timestamptz NOT NULL DEFAULT now(),
+  deleted_at timestamptz
+);
+--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS media_objects_owner_idx ON media_objects(owner_id, created_at DESC);
+--> statement-breakpoint
+CREATE INDEX IF NOT EXISTS media_objects_couple_idx ON media_objects(couple_id) WHERE couple_id IS NOT NULL;
+--> statement-breakpoint
+CREATE TABLE IF NOT EXISTS media_deletion_queue (
+  storage_key text PRIMARY KEY,
+  queued_at timestamptz NOT NULL DEFAULT now()
+);
+--> statement-breakpoint
+CREATE OR REPLACE FUNCTION queue_media_blob_deletion() RETURNS trigger LANGUAGE plpgsql AS $$
+BEGIN
+  INSERT INTO media_deletion_queue(storage_key) VALUES(OLD.storage_key) ON CONFLICT DO NOTHING;
+  RETURN OLD;
+END $$;
+--> statement-breakpoint
+DROP TRIGGER IF EXISTS media_objects_queue_blob_deletion ON media_objects;
+CREATE TRIGGER media_objects_queue_blob_deletion BEFORE DELETE ON media_objects
+FOR EACH ROW EXECUTE FUNCTION queue_media_blob_deletion();
+--> statement-breakpoint
+ALTER TABLE feedback ADD COLUMN IF NOT EXISTS screenshot_media_id uuid REFERENCES media_objects(id) ON DELETE SET NULL;