Add seedbox lifecycle state machine

[phucnguyen1707]

Summary:

• add a seedbox lifecycle helper for the PRD statuses from pending through terminated/failed
• add guarded transitions plus timestamp stamping for activation and termination
• cover valid paths, invalid jumps, failed retries, terminal states, and timestamp behavior with Vitest tests

Deferred intentionally:

• secure wipe on terminate, audit events, provisioning workers, and database migration wiring stay out of this small lifecycle slice

Validation:

• pnpm test src/lib/seedbox/lifecycle.test.ts
• pnpm exec tsc --noEmit --pretty false
• pnpm exec eslint src/lib/seedbox
• git diff --check
• pre-commit hook also ran formatter, typecheck, and the full test suite: 150 test files, 2248 tests passed, 3 skipped

Note:

• local Node is v22.22.2 while package.json requests >=24.0.0; the targeted checks and pre-commit suite passed under the local environment.