chore(db): renumber model_capabilities migration 163 → 169 (cross-branch collision with 163_radar_feed_cache_generated_at)

#11845 landed on main as 163 while release/v3.8.51 had already used 163–168.
Per the cross-PR collision precedent (#3365/#3371) the later arrival takes the
next free number; the SQL is idempotent, so installs that already ran it as
163 on main are unaffected.

src/lib/db/migrations/169_model_capabilities.sql

@@ -1,4 +1,4 @@
--- 163_model_capabilities.sql
+-- 169_model_capabilities.sql
 --
 -- Promote `model_capabilities` from a lazily-created runtime table to a real migration.
 --