docs: RFC-002 Input + Definition of Done + Compliance Matrix update

- RFC_DEFINITION_OF_DONE.md (v1.0, LOCKED):
  - 12 criteria for every RFC component
  - Sign-off roles: Author, Reviewer, Automated, QA
  - Exit criteria: all 12 must pass

- RFC-002: Canonical Input Component:
  - Cognitive Purpose: captures free-form text/numeric data
  - When to Use/NOT Use: clear boundaries vs Select, Switch, Date Picker
  - Interaction Contract: click, type, tab, blur, enter, escape
  - Failure Behaviour: invalid, network, max length, required, disabled
  - Accessibility Contract: label, focus, error, required, screen reader
  - AI Contract: when to choose Input vs alternatives
  - Token Dependencies: 13 tokens (bg, border, text, padding, radius, sizes, states)
  - Layout, Sizes (sm/md/lg), Variants (default/ghost/filled), States (8 states)
  - Keyboard, Touch, Motion (with reduced motion)
  - Anti-Patterns: placeholder as label, validation only on submit, etc.
  - Related Components: Select, Textarea, Search, Form, Label
  - DDR References: DDR-001, DDR-002, DDR-003
  - Acceptance Criteria: 10 checklist items

- COMPLIANCE_MATRIX.md: Input updated to 33% (Governance 🟡, Tokens 🟡,
  Motion 🟡, Accessibility 🟡, AI ✅, QA ⏳)

Rationale: Validate RFC-001 template works for different component types.
Definition of Done ensures consistent quality. Compliance Matrix tracks
progress visibly.

docs/design/COMPLIANCE_MATRIX.md

@@ -23,7 +23,7 @@
 | Component | Governance | Tokens | Motion | Accessibility | AI | QA | Overall |
 |-----------|------------|--------|--------|---------------|-----|-----|---------|
 | Button | ✅ | ✅ | ✅ | 🟡 | ✅ | ⏳ | 82% |
-| Input | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | 0% |
+| Input | 🟡 | 🟡 | 🟡 | 🟡 | ✅ | ⏳ | 33% |
 | Select | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | 0% |
 | Card | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | 0% |
 | Modal | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | ⏳ | 0% |