fix: address code review issues for RPM limiting feature

- Use TxPipeline (MULTI/EXEC) instead of Pipeline for atomic INCR+EXPIRE
- Filter negative values in GetBaseRPM(), update test expectation
- Add RPM batch query (GetRPMBatch) to account List API
- Add warn logs for RPM increment failures in gateway handler
- Reset enableRpmLimit on BulkEditAccountModal close
- Use union type 'tiered' | 'sticky_exempt' for rpmStrategy refs
- Add design decision comments for rdb.Time() RTT trade-off

frontend/src/i18n/locales/en.ts

@@ -1618,6 +1618,13 @@ export default {
           full: 'RPM limit reached',
           warning: 'RPM approaching limit',
           normal: 'RPM normal',
+          tieredNormal: 'RPM limit (Tiered) - Normal',
+          tieredWarning: 'RPM limit (Tiered) - Approaching limit',
+          tieredStickyOnly: 'RPM limit (Tiered) - Sticky only | Buffer: {buffer}',
+          tieredBlocked: 'RPM limit (Tiered) - Blocked | Buffer: {buffer}',
+          stickyExemptNormal: 'RPM limit (Sticky Exempt) - Normal',
+          stickyExemptWarning: 'RPM limit (Sticky Exempt) - Approaching limit',
+          stickyExemptOver: 'RPM limit (Sticky Exempt) - Over limit, sticky only'
         },
       },
       tempUnschedulable: {
@@ -1842,7 +1849,12 @@ export default {
           strategy: 'RPM Strategy',
           strategyTiered: 'Tiered Model',
           strategyStickyExempt: 'Sticky Exempt',
+          strategyTieredHint: 'Green → Yellow → Sticky only → Blocked, progressive throttling',
+          strategyStickyExemptHint: 'Only sticky sessions allowed when over limit',
           strategyHint: 'Tiered: gradually restrict when exceeded; Sticky Exempt: existing sessions unrestricted',
+          stickyBuffer: 'Sticky Buffer',
+          stickyBufferPlaceholder: 'Default: 20% of base RPM',
+          stickyBufferHint: 'Extra requests allowed for sticky sessions after exceeding base RPM. Leave empty to use default (20% of base RPM, min 1)'
         },
         tlsFingerprint: {
           label: 'TLS Fingerprint Simulation',