docs(04-02): complete download utilities and OutputBlock plan

- 04-02-SUMMARY.md: execution summary for download utilities and OutputBlock
- STATE.md: progress updated to 83%, decisions recorded, session updated
- ROADMAP.md: phase 4 plan progress updated (2/5 summaries)

.planning/ROADMAP.md

@@ -95,4 +95,4 @@ Phases execute in numeric order: 1 → 2 → 3 → 4
 | 1. Foundation | 4/4 | Complete   | 2026-03-26 |
 | 2. Generators | 4/4 | Complete   | 2026-03-26 |
 | 3. Wizard UI | 5/5 | Complete   | 2026-03-27 |
-| 4. Review, Download & Security | 0/5 | Not started | - |
+| 4. Review, Download & Security | 2/5 | In Progress|  |

.planning/STATE.md

@@ -3,14 +3,14 @@ gsd_state_version: 1.0
 milestone: v1.0
 milestone_name: milestone
 status: executing
-stopped_at: Completed 04-review-download-security-04-01-PLAN.md
+stopped_at: Completed 04-review-download-security-04-02-PLAN.md
-last_updated: "2026-03-27T10:42:17.960Z"
+last_updated: "2026-03-27T10:46:35.092Z"
 last_activity: 2026-03-26 — Completed plan 01-02 (Backend Schema Registry)
 progress:
   total_phases: 4
   completed_phases: 3
   total_plans: 18
-  completed_plans: 14
+  completed_plans: 15
   percent: 50
 ---
 
@@ -62,6 +62,7 @@ Progress: [█████░░░░░] 50%
 | Phase 03-wizard-ui P05 | 5min | 2 tasks | 5 files |
 | Phase 03-wizard-ui P05 | 5min | 3 tasks | 5 files |
 | Phase 04-review-download-security P01 | 2min | 2 tasks | 2 files |
+| Phase 04-review-download-security P02 | 2min | 2 tasks | 5 files |
 
 ## Accumulated Context
 
@@ -107,6 +108,9 @@ Recent decisions affecting current work:
 - [Phase 03-wizard-ui]: [03-05] Human verification approved — full 3-step wizard flow confirmed working end-to-end
 - [Phase 04-review-download-security]: [04-01] Wave 0 stubs use expect.fail — named RED baseline for all 10 ReviewStep requirements, consistent with Phase 3 pattern
 - [Phase 04-review-download-security]: [04-01] SECU-03 assertion placed in reducer.test.ts — reducer is the state boundary that must never touch storage
+- [Phase 04-review-download-security]: No src/utils/index.ts barrel — direct imports keep test mock paths predictable
+- [Phase 04-review-download-security]: Do NOT install @types/jszip — JSZip 3.x ships own TypeScript declarations
+- [Phase 04-review-download-security]: OutputBlock disabled prop gates both Copy and Download buttons — visual opacity-40 without hiding (SECU-01 gate)
 
 ### Pending Todos
 
@@ -120,6 +124,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-27T10:42:17.955Z
+Last session: 2026-03-27T10:46:29.087Z
-Stopped at: Completed 04-review-download-security-04-01-PLAN.md
+Stopped at: Completed 04-review-download-security-04-02-PLAN.md
 Resume file: None

.planning/phases/04-review-download-security/04-02-SUMMARY.md

@@ -0,0 +1,119 @@
+---
+phase: 04-review-download-security
+plan: 02
+subsystem: ui
+tags: [react, typescript, jszip, blob-download, clipboard, tailwind]
+
+# Dependency graph
+requires:
+  - phase: 04-01
+    provides: Wave 0 test stubs for ReviewStep (RED baseline)
+  - phase: 02-generators
+    provides: Generator functions used by OutputBlock consumers
+provides:
+  - src/utils/downloadFile.ts — pure Blob+anchor download utility
+  - src/utils/downloadZip.ts — JSZip archive builder with Blob download
+  - src/components/wizard/OutputBlock.tsx — reusable code block with copy and optional download buttons
+affects:
+  - 04-03 (ReviewStep will import all three artifacts)
+  - 04-04 (security gate applied via OutputBlock disabled prop)
+
+# Tech tracking
+tech-stack:
+  added:
+    - jszip ^3.10.1 (runtime dependency — client-side ZIP generation)
+  patterns:
+    - Blob + URL.createObjectURL + anchor click for file download (no FileSaver dependency)
+    - JSZip generateAsync({ type: 'blob' }) for ZIP bundle download
+    - navigator.clipboard.writeText with useState feedback (2s "Copied!" label)
+    - disabled prop gates both copy and download actions (SECU-01 pattern)
+
+key-files:
+  created:
+    - src/utils/downloadFile.ts
+    - src/utils/downloadZip.ts
+    - src/components/wizard/OutputBlock.tsx
+  modified:
+    - package.json (jszip added to dependencies)
+    - package-lock.json
+
+key-decisions:
+  - "No src/utils/index.ts barrel — direct imports keep test mock paths predictable (../../utils/downloadFile)"
+  - "Do NOT install @types/jszip — JSZip 3.x ships its own TypeScript declarations (stale package 6 years old)"
+  - "OutputBlock renders Download button conditionally on filename prop presence — not hidden, rendered when applicable"
+  - "disabled prop passed as HTML disabled attribute to both Copy and Download buttons — visual opacity-40 communicates lock state"
+
+patterns-established:
+  - "Pattern: Blob download helper — create Blob, createObjectURL, hidden anchor click, revokeObjectURL immediately after click"
+  - "Pattern: OutputBlock disabled gate — parent passes disabled={!acknowledged} to apply SECU-01 per-block"
+
+requirements-completed: [DOWN-01, DOWN-02, DOWN-03, DOWN-04, DOWN-05, DOWN-06, CONF-03]
+
+# Metrics
+duration: 2min
+completed: 2026-03-27
+---
+
+# Phase 4 Plan 02: Download Utilities and OutputBlock Summary
+
+**Blob/anchor download utility, JSZip ZIP builder, and reusable OutputBlock component with clipboard copy and per-block disabled security gate**
+
+## Performance
+
+- **Duration:** 2 min
+- **Started:** 2026-03-27T10:43:40Z
+- **Completed:** 2026-03-27T10:45:30Z
+- **Tasks:** 2
+- **Files modified:** 5
+
+## Accomplishments
+
+- Created `downloadFile` utility using native Blob + createObjectURL + anchor pattern (no FileSaver dependency)
+- Created `downloadZip` utility using JSZip generateAsync — installed jszip as the only new runtime dependency in phase 4
+- Created `OutputBlock` reusable component with copy button (clipboard.writeText with 2s feedback), optional download button, and SECU-01 disabled gate via prop
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Create downloadFile.ts and downloadZip.ts utilities** - `f948b86` (feat)
+2. **Task 2: Create OutputBlock.tsx reusable component** - `e223e8b` (feat)
+
+**Plan metadata:** (docs commit — see below)
+
+## Files Created/Modified
+
+- `src/utils/downloadFile.ts` — Pure browser download: Blob + createObjectURL + anchor click + revokeObjectURL
+- `src/utils/downloadZip.ts` — JSZip ZIP builder: loops file entries, generateAsync blob, same anchor download pattern
+- `src/components/wizard/OutputBlock.tsx` — Labelled code block with copy button (clipboard + 2s feedback), optional download button, disabled prop gate
+- `package.json` — jszip ^3.10.1 added to dependencies
+- `package-lock.json` — lock file updated
+
+## Decisions Made
+
+- No barrel file `src/utils/index.ts` — direct imports from specific utility files keep test mock paths predictable (the Wave 0 test file mocks `../../utils/downloadFile` and `../../utils/downloadZip` by exact path)
+- `@types/jszip` intentionally omitted — JSZip 3.x ships its own TypeScript declarations; `@types/jszip` is 6 years stale and causes type conflicts
+- OutputBlock Download button rendered conditionally on `filename` prop presence — if no filename, no download button; both Copy and Download always visible when applicable (never hidden while disabled)
+- `disabled:opacity-40` Tailwind class communicates lock state visually without hiding buttons
+
+## Deviations from Plan
+
+None — plan executed exactly as written. Utility implementations match the specification in the plan verbatim. Build pre-existing TypeScript errors (in test files and vite.config.ts) were confirmed pre-existing and out of scope.
+
+## Issues Encountered
+
+`npm run build` surfaces pre-existing TypeScript errors in `*.test.ts` files (vitest globals not typed in tsconfig) and `vite.config.ts` (`test` property). These are known pre-existing issues unrelated to this plan's changes. TypeScript compilation of the new source files is clean (verified via `tsc --noEmit --skipLibCheck`).
+
+## User Setup Required
+
+None — no external service configuration required.
+
+## Next Phase Readiness
+
+- `downloadFile`, `downloadZip`, and `OutputBlock` are ready for ReviewStep to compose in plan 04-03
+- ReviewStep.test.tsx remains RED (ReviewStep file does not exist yet — expected at this stage)
+- All 11 other test files remain GREEN (88 tests passing)
+
+---
+*Phase: 04-review-download-security*
+*Completed: 2026-03-27*