fix(i18n): multi-syllable verb doubling and template caching
1. Add stressed-final-syllable verbs to irregularVerbs:
- submit, permit, admit, omit, commit, transmit
- prefer, refer, transfer, defer, confer, infer
- occur, recur, incur, deter, control, patrol
- compel, expel, propel, repel, rebel, excel
2. Add UK English -l doubling (cancel→cancelled, travel→travelled)
3. Add template caching to applyTemplate() matching executeIntentTemplate()
for consistent performance.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>