File-size decomposition (no behavior change). Move the state-free TinyEventEmitter,
the decrypt-retry helpers (isTransientDecryptError, computeRetryDelay + tables),
the normalize helpers (normalizeHexPubkey, normalizeEncryptionToken), and the
subscription-list codec (serializeSubscriptionTagMatrix, parseSubscriptionPlaintext,
parseCachedSubscriptionSnapshot) into js/subscriptionsHelpers.js.
subscriptions.js: 2584 -> 2361 lines (below its original 2426 baseline;
re-recorded to 2361 to lock the reduction).
Build + full unit suite green.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
thePR0M3TH3AN