docs(09-04): complete BackendSelectionStep TextFieldMD3 gap closure plan

- 09-04-SUMMARY.md: all 1 tasks documented, 179 tests green
- STATE.md: position advanced, session updated
- ROADMAP.md: Phase 9 marked 4/4 plans complete

.planning/ROADMAP.md

@@ -66,7 +66,7 @@ Plans:
   3. Backend selection cards and output blocks display MD3 elevation with tonal surface tint and consistent shape tokens
   4. Step indicator shows numbered circles connected by lines, with checkmarks on completed steps, highlight on current, and muted future steps
   5. FieldRenderer produces identical `aria-label` attributes for both text-branch and select-branch inputs
-**Plans:** 4 plans (3 complete, 1 gap closure)
+**Plans:** 4/4 plans complete
 Plans:
 - [x] 09-01-PLAN.md — TextFieldMD3 component, MD3 button constants, DEBT-01 aria-label fix
 - [x] 09-02-PLAN.md — StepIndicator rebuild with MD3 circles and connectors
@@ -107,6 +107,6 @@ Plans:
 | 6. New Backends | v1.1 | 4/4 | Complete | 2026-03-31 |
 | 7. Validation & UX Polish | v1.1 | 3/3 | Complete | 2026-03-31 |
 | 8. Theme Foundation | v1.2 | 2/2 | Complete | 2026-04-01 |
-| 9. MD3 Components | v1.2 | 3/4 | Gap closure | - |
+| 9. MD3 Components | 4/4 | Complete   | 2026-04-01 | - |
 | 10. Content & Clarity | v1.2 | 0/? | Not started | - |
 | 11. Polish & Responsiveness | v1.2 | 0/? | Not started | - |

.planning/STATE.md

@@ -2,15 +2,15 @@
 gsd_state_version: 1.0
 milestone: v1.2
 milestone_name: UI Polish & Clarity
-status: in-progress
+status: completed
-stopped_at: "Completed 09-03 — Full MD3 component integration: floating labels, button hierarchy, card elevation"
+stopped_at: "Completed 09-04 — BackendSelectionStep TextFieldMD3 gap closure: all 12/12 wizard must-have truths satisfied"
-last_updated: "2026-04-01T08:00:00Z"
+last_updated: "2026-04-01T08:28:33.355Z"
 last_activity: 2026-04-01 — Phase 9 complete (COMP-01, COMP-02, COMP-03, COMP-04, DEBT-01 satisfied)
 progress:
   total_phases: 4
   completed_phases: 2
-  total_plans: 7
+  total_plans: 6
-  completed_plans: 7
+  completed_plans: 6
   percent: 64
 ---
 
@@ -54,6 +54,7 @@ Recent decisions affecting current work:
 - [Phase 09-03]: Tooltip button rendered ABOVE TextFieldMD3 in FieldRenderer (tooltip is separate concern, TextFieldMD3 is self-contained)
 - [Phase 09-03]: PasswordField show/hide toggle passed as suffix prop to TextFieldMD3 — suffix slot is right-aligned inside input container
 - [Phase 09-03]: OutputBlock Copy/Download buttons use MD3_BTN_OUTLINED with !text-xs !px-3 !py-1.5 overrides to preserve small utility button size
+- [Phase 09-md3-components]: BackendSelectionStep gap: plain label+input replaced with TextFieldMD3; no test changes required because TextFieldMD3 preserves textbox role and role=alert contract
 
 ### Pending Todos
 
@@ -65,6 +66,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-04-01T08:00:00Z
+Last session: 2026-04-01T08:28:33.352Z
-Stopped at: Completed 09-03 — Full MD3 component integration: floating labels, button hierarchy, card elevation
+Stopped at: Completed 09-04 — BackendSelectionStep TextFieldMD3 gap closure: all 12/12 wizard must-have truths satisfied
 Resume file: None

.planning/phases/09-md3-components/09-04-SUMMARY.md

@@ -0,0 +1,94 @@
+---
+phase: 09-md3-components
+plan: "04"
+subsystem: ui
+tags: [react, tailwind, md3, textfield, floating-label, react-hook-form]
+
+# Dependency graph
+requires:
+  - phase: 09-md3-components/09-03
+    provides: TextFieldMD3 component with floating label, FieldRenderer integration
+provides:
+  - BackendSelectionStep Remote name field migrated to TextFieldMD3
+  - COMP-01 "All text inputs" requirement fully satisfied (12/12 wizard must-have truths)
+affects: [Phase 10, verification]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns: [TextFieldMD3 registration prop pattern extended to BackendSelectionStep]
+
+key-files:
+  created: []
+  modified:
+    - src/components/wizard/BackendSelectionStep.tsx
+
+key-decisions:
+  - "BackendSelectionStep gap: plain label+input replaced with TextFieldMD3; no test changes required — getByRole('textbox') and role='alert' preserved by TextFieldMD3 internals"
+
+patterns-established:
+  - "All wizard text inputs now use TextFieldMD3 with registration prop pattern"
+
+requirements-completed: [COMP-01, COMP-02, COMP-03, COMP-04, DEBT-01]
+
+# Metrics
+duration: 5min
+completed: 2026-04-01
+---
+
+# Phase 9 Plan 04: BackendSelectionStep TextFieldMD3 Gap Closure Summary
+
+**TextFieldMD3 floating-label replaces BackendSelectionStep's plain Remote name input, closing the last COMP-01 gap and achieving 12/12 wizard must-have truths**
+
+## Performance
+
+- **Duration:** 5 min
+- **Started:** 2026-04-01T10:26:00Z
+- **Completed:** 2026-04-01T10:31:00Z
+- **Tasks:** 1
+- **Files modified:** 1
+
+## Accomplishments
+- Replaced `<label htmlFor="remote-name"> + <input> + <p role="alert">` block with `<TextFieldMD3>` in BackendSelectionStep
+- Added `import { TextFieldMD3 } from '../ui/TextFieldMD3'` to the component
+- All 10 BackendSelectionStep tests pass without modification (textbox role and alert role preserved by TextFieldMD3 internals)
+- Full suite of 179 tests remains green, zero regressions
+- COMP-01 "All text inputs use floating label" requirement fully satisfied across all wizard steps
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Replace plain Remote name input with TextFieldMD3** - `123f24c` (feat)
+
+**Plan metadata:** _(pending final docs commit)_
+
+## Files Created/Modified
+- `src/components/wizard/BackendSelectionStep.tsx` - TextFieldMD3 integration replacing plain label+input block
+
+## Decisions Made
+- No test changes needed: TextFieldMD3 renders `<input>` (preserving `getByRole('textbox')`) and `<p role="alert">` on error (preserving `getByRole('alert')`) — exact same DOM contract as the replaced plain elements
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+None.
+
+## User Setup Required
+None - no external service configuration required.
+
+## Next Phase Readiness
+- Phase 9 verification truth #12 can now be confirmed as VERIFIED (12/12 truths satisfied)
+- COMP-01, COMP-02, COMP-03, COMP-04, DEBT-01 requirements fully closed
+- Ready for Phase 10
+
+---
+*Phase: 09-md3-components*
+*Completed: 2026-04-01*
+
+## Self-Check: PASSED
+- FOUND: src/components/wizard/BackendSelectionStep.tsx
+- FOUND: .planning/phases/09-md3-components/09-04-SUMMARY.md
+- FOUND: commit 123f24c