docs(39-02): complete voice hardware detection plan

- Add 39-02-SUMMARY.md with task results and self-check
- Update STATE.md progress (92%), decisions, session
- Update ROADMAP.md phase 39 progress (2 plans, 1 summary)
- Mark requirements ONBRD-01, ONBRD-02 complete

.planning/REQUIREMENTS.md

@@ -36,8 +36,8 @@
 
 ### Onboarding
 
-- [ ] **ONBRD-01**: Onboarding hardware probe detects Whisper STT and Piper TTS capability
-- [ ] **ONBRD-02**: Onboarding presents voice enable/skip step based on hardware detection results
+- [x] **ONBRD-01**: Onboarding hardware probe detects Whisper STT and Piper TTS capability
+- [x] **ONBRD-02**: Onboarding presents voice enable/skip step based on hardware detection results
 - [x] **ONBRD-03**: Guided BotFather setup flow for Telegram bot token during onboarding
 
 ## Future Requirements
@@ -92,8 +92,8 @@
 | TGRAM-04 | Phase 38 | Complete |
 | TGRAM-05 | Phase 38 | Complete |
 | TGRAM-06 | Phase 38 | Complete |
-| ONBRD-01 | Phase 39 | Pending |
-| ONBRD-02 | Phase 39 | Pending |
+| ONBRD-01 | Phase 39 | Complete |
+| ONBRD-02 | Phase 39 | Complete |
 | ONBRD-03 | Phase 38 | Complete |
 
 **Coverage:**

.planning/phases/39-voice-polish/39-02-SUMMARY.md

@@ -0,0 +1,87 @@
+---
+phase: 39-voice-polish
+plan: "02"
+subsystem: onboarding-voice
+tags: [hardware-detection, voice, onboarding, tdd]
+dependency_graph:
+  requires: []
+  provides: [voice-capability-probe, hardware-aware-voice-step]
+  affects: [server/src/services/hardware.ts, ui/src/components/onboarding/VoiceStep.tsx]
+tech_stack:
+  added: []
+  patterns: [execFile-async-wrapper, tdd-red-green, conditional-ui-rendering]
+key_files:
+  created:
+    - server/src/__tests__/39-voice-hardware-probe.test.ts
+  modified:
+    - server/src/services/hardware.ts
+    - ui/src/api/hardware.ts
+    - ui/src/hooks/useHardwareInfo.ts
+    - ui/src/components/onboarding/VoiceStep.tsx
+    - ui/src/components/NexusOnboardingWizard.tsx
+decisions:
+  - "Used execFile callback wrapper (not promisify) for consistent mocking in vitest — same pattern as voice-pipeline.ts"
+  - "withVoiceTimeout wraps the entire detectVoiceCapability() call with 3s fallback to avoid slowing hardware detection"
+  - "voiceCapability is optional (?) in the UI HardwareInfo type for backward compatibility if server not updated"
+  - "VoiceStep does NOT auto-skip on insufficient hardware — user reads the note and skips manually"
+metrics:
+  duration: "~4 minutes"
+  completed_date: "2026-04-04"
+  tasks_completed: 2
+  files_changed: 5
+---
+
+# Phase 39 Plan 02: Onboarding Voice Hardware Detection Summary
+
+Voice capability probe added to hardware service (whisper-cpp/whisper + piper binary detection with 2s timeout each), and VoiceStep updated with hardware-aware conditional UI based on detected capabilities.
+
+## Tasks Completed
+
+| Task | Name | Commit | Files |
+|------|------|--------|-------|
+| 1 | Voice capability probe in hardware service | 175fde59 | server/src/services/hardware.ts, server/src/__tests__/39-voice-hardware-probe.test.ts |
+| 2 | VoiceStep hardware-aware UI with conditional enable/skip | 003d6416 | ui/src/api/hardware.ts, ui/src/hooks/useHardwareInfo.ts, ui/src/components/onboarding/VoiceStep.tsx, ui/src/components/NexusOnboardingWizard.tsx |
+
+## What Was Built
+
+**Task 1 — Voice capability probe:**
+- Added `VoiceCapability` interface: `{ whisperAvailable, piperAvailable, voiceTierSufficient }`
+- Extended `HardwareInfo` with `voiceCapability: VoiceCapability`
+- `detectVoiceCapability()` probes whisper-cpp (falls back to whisper) and piper with 2s timeout each
+- `voiceTierSufficient` = true for apple_silicon/gpu, or cpu_only with >= 4GB free RAM
+- Wrapped in 3s `withVoiceTimeout()` to prevent voice probes from slowing hardware detection
+- GET /system/providers automatically includes voiceCapability (no route changes needed)
+- 6 TDD tests covering all binary combinations and tier sufficiency logic
+
+**Task 2 — Hardware-aware VoiceStep:**
+- VoiceStep accepts optional `voiceCapability` prop (backward-compatible)
+- Insufficient hardware: shows amber warning note + Skip button only (no Enable)
+- Binaries detected: shows green CheckCircle2 icons next to STT/TTS labels
+- Missing binaries but sufficient hardware: blue install note, outline Enable + Skip
+- No hardware info (loading/undefined): falls back to original mic-only behavior
+- NexusOnboardingWizard passes `hardwareInfo?.voiceCapability` to VoiceStep at step 4
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Known Stubs
+
+None.
+
+## Self-Check: PASSED
+
+Files created/modified:
+- FOUND: server/src/services/hardware.ts
+- FOUND: server/src/__tests__/39-voice-hardware-probe.test.ts
+- FOUND: ui/src/api/hardware.ts
+- FOUND: ui/src/hooks/useHardwareInfo.ts
+- FOUND: ui/src/components/onboarding/VoiceStep.tsx
+- FOUND: ui/src/components/NexusOnboardingWizard.tsx
+
+Commits:
+- FOUND: 1851c513 (TDD RED — failing tests)
+- FOUND: 175fde59 (TDD GREEN — hardware service implementation)
+- FOUND: 003d6416 (VoiceStep UI + wizard wiring)
+
+Tests: 6/6 passing