feat(db): migration 012 — advanced features schema

Add 'trim' to job_type enum, create temp_segments table with
expiry/job/asset indexes, and add conform_source_sequence_id
to assets for lineage tracking.

Closes #33

services/mam-api/src/db/migrations/012-advanced-features.sql

@@ -0,0 +1,31 @@
+-- 2026-05: Advanced features — trim jobs, temp segments, conform tracking.
+-- Idempotent: safe to re-run (IF NOT EXISTS / DO $$ BEGIN guards throughout).
+
+-- 1. Add 'trim' to job_type enum
+DO $$
+BEGIN
+  IF NOT EXISTS (SELECT 1 FROM pg_enum WHERE enumlabel = 'trim' AND enumtypid = 'job_type'::regtype) THEN
+    ALTER TYPE job_type ADD VALUE 'trim';
+  END IF;
+END $$;
+
+-- 2. Temp segments table — tracks per-clip trimmed hi-res segments
+--    with a 24-hour TTL for auto-cleanup.
+CREATE TABLE IF NOT EXISTS temp_segments (
+  id               UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+  job_id           UUID NOT NULL REFERENCES jobs(id) ON DELETE CASCADE,
+  clip_instance_id UUID NOT NULL,
+  asset_id         UUID NOT NULL REFERENCES assets(id) ON DELETE CASCADE,
+  s3_key           TEXT NOT NULL,
+  expires_at       TIMESTAMPTZ NOT NULL,
+  created_at       TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_temp_segments_expires_at ON temp_segments(expires_at);
+CREATE INDEX IF NOT EXISTS idx_temp_segments_job_id      ON temp_segments(job_id);
+CREATE INDEX IF NOT EXISTS idx_temp_segments_asset_id     ON temp_segments(asset_id);
+
+-- 3. Asset conform tracking — remember which sequence this asset was
+--    conformed from so the UI can show lineage and prevent double-conform.
+ALTER TABLE assets ADD COLUMN IF NOT EXISTS conform_source_sequence_id UUID REFERENCES sequences(id);
+CREATE INDEX IF NOT EXISTS idx_assets_conform_source ON assets(conform_source_sequence_id);