feat(ui): add "연락처별 문구" screen with contact picker

ContactTemplatesActivity lets the user pick a contact, a trigger,
and a template. Overrides are stored via TemplateRepo.setOverride()
and displayed as a card list with per-card delete. Entry point is a
new outlined button below "문구 관리" in SettingsActivity.

Constraint: number passed to setOverride() must already be PhoneNorm-normalised (done in chooseTriggerThenTemplate).
Confidence: high
Scope-risk: local
Reversibility: trivial
Directive: keep ContactTemplatesActivity under 200 lines; split if card/dialog logic grows
Tested: assembleDebug succeeds; 35 unit tests pass; layout inflated without resource errors
Not-tested: actual contact picker flow on device; READ_CONTACTS permission denial path
Related: Phase 2 per-contact template override

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