feat(scheduler): random run-window scheduling and deduped manual triggers

Support a random daily run window (random_window_start/end) where the
next auto-run time is derived from a stable per-job hash, avoiding
thundering-herd starts while keeping one run per day. Honors the last
auto-run on initial scheduling so restarts don't double-fire.

Manual triggers can opt into dedupe (dedupe_manual_triggers): an
advisory-locked path collapses concurrent requests onto an existing
pending/running job instead of queueing duplicates. Scheduler error
messages are localized to Chinese.

Register the media_supply_cache_sync job (dry-run aware) and add the
ops migration that seeds it.

server/migrations_ops/20260602130000_add_media_supply_cache_sync_scheduler_job.down.sql

@@ -0,0 +1,8 @@
+DELETE FROM ops.scheduler_job_triggers
+WHERE job_key = 'media_supply_cache_sync';
+
+DELETE FROM ops.scheduler_job_runs
+WHERE job_key = 'media_supply_cache_sync';
+
+DELETE FROM ops.scheduler_jobs
+WHERE job_key = 'media_supply_cache_sync';

server/migrations_ops/20260602130000_add_media_supply_cache_sync_scheduler_job.up.sql

@@ -0,0 +1,27 @@
+INSERT INTO ops.scheduler_jobs
+    (job_key, display_name, category, description, enabled, schedule_type, interval_seconds, timezone, timeout_seconds, batch_size, config)
+VALUES
+    (
+        'media_supply_cache_sync',
+        '媒体资源缓存同步',
+        'media_supply',
+        '每日低频同步权威媒体资源缓存，并在成本价上涨超过手动售价时清理手动改价。',
+        true,
+        'interval',
+        86400,
+        'Asia/Shanghai',
+        3600,
+        1,
+        '{"model_id":1,"random_window_start":"01:00","random_window_end":"04:00","dedupe_manual_triggers":true}'::jsonb
+    )
+ON CONFLICT (job_key) DO UPDATE
+SET display_name = EXCLUDED.display_name,
+    category = EXCLUDED.category,
+    description = EXCLUDED.description,
+    schedule_type = EXCLUDED.schedule_type,
+    interval_seconds = EXCLUDED.interval_seconds,
+    timezone = EXCLUDED.timezone,
+    timeout_seconds = EXCLUDED.timeout_seconds,
+    batch_size = EXCLUDED.batch_size,
+    config = ops.scheduler_jobs.config || EXCLUDED.config,
+    updated_at = NOW();