Optimize / Storage migrations

[sonytooo]

Optimize storage migration sweep

StorageController ran 20 migrations on every boot, and since get/set/remove all block on that sweep, it held up app load (especially on mobile, where each storage call is a postMessage round-trip to native RN storage).

Each migration re-read passedMigrations and read its data keys before checking whether it had already run. In the steady state (returning user, everything already migrated) this meant ~41 reads + ~3 writes on every single launch.

Changes

• Read passedMigrations once into an in-memory Set; every migration now checks it first and returns before touching storage.
• passedMigrations is written only when a migration actually does work (#markMigrationPassed).
• Added missing guards to 4 migrations that previously ran (and 2 that wrote) on every boot.

No behavioral change - each migration performs the same transformation under the same conditions; only redundant I/O was removed.

Result

Steady-state boot: ~44 storage requests -> 1 (~97% fewer).

Tests

Added migration sweep performance tests asserting a fully-migrated install does 1 read / 0 writes, and that the newly-guarded migrations don't re-run.

[PetromirDev]

👏