perf(ext/node): convert internal/crypto to lazy-loaded JS (#33919)
**internal/crypto (14 files → IIFE):**
- `_randomBytes.ts`, `_randomFill.mjs`, `certificate.ts`, `cipher.ts`,
`diffiehellman.ts`, `hash.ts`, `hkdf.ts`, `keygen.ts`, `keys.ts`,
`pbkdf2.ts`, `random.ts`, `scrypt.ts`, `sig.ts`, `x509.ts`
- Cross-deps use `core.loadExtScript`; `node:process`, `node:stream`,
`node:_stream_writable` use `core.createLazyLoader`
- `keys.ts` ↔ `cipher.ts` circular dependency handled with deferred
loading
- `Hash`, `Hmac`, `Sign`, `Verify` prototype chains deferred via
`ensureProtoSetup` pattern
