docs(02-01): complete prompt CRUD + prompt editor plan

Tasks completed: 2/2
- Backend prompts router with 4 CRUD endpoints
- Frontend Prompt Editor page with types, hooks, route, sidebar

SUMMARY: .planning/phases/02-prompt-control-output-review/02-01-SUMMARY.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.planning/phases/02-prompt-control-output-review/02-01-SUMMARY.md

@@ -0,0 +1,101 @@
+---
+phase: 02-prompt-control-output-review
+plan: 01
+subsystem: prompt-management
+tags: [fastapi, react, crud, prompt-editor, tanstack-query]
+
+dependency_graph:
+  requires:
+    - 01-02 (PromptService with load/save/list/variables/exists methods)
+    - 01-04 (Web UI with stone/amber palette, Sidebar, Layout, routing)
+  provides:
+    - Prompt CRUD API (4 endpoints: list, read, write, reset)
+    - Prompt Editor UI page with live variable extraction
+  affects:
+    - 02-02 (Output Review enhancement may reference prompt editing)
+    - Future phases that add new prompt types
+
+tech_stack:
+  added: []
+  patterns:
+    - Lazy PromptService init for directory lifecycle sync
+    - Default vs modified comparison for prompt versioning
+    - Client-side regex for live variable extraction
+
+key_files:
+  created:
+    - backend/routers/prompts.py
+    - frontend/src/pages/PromptEditor.tsx
+  modified:
+    - backend/main.py
+    - frontend/src/types.ts
+    - frontend/src/api/hooks.ts
+    - frontend/src/App.tsx
+    - frontend/src/components/Sidebar.tsx
+
+decisions:
+  - id: prompt-lazy-init
+    decision: "PromptService initialized lazily via _get_prompt_service() instead of module-level"
+    reason: "PROMPTS_PATH directory is created during FastAPI lifespan, not at import time. Module-level init would fail with FileNotFoundError during import."
+    date: 2026-03-08
+
+metrics:
+  duration: ~5 min
+  completed: 2026-03-08
+---
+
+# Phase 02 Plan 01: Prompt CRUD + Prompt Editor UI Summary
+
+**PromptService CRUD completo con 4 endpoint FastAPI e pagina React Prompt Editor con lista, textarea monospace, variabili live, salva e reset al default.**
+
+## What Was Done
+
+### Task 1: Backend prompts router (4 CRUD endpoints)
+Created `backend/routers/prompts.py` with `APIRouter(prefix="/api/prompts", tags=["prompts"])`:
+
+- **GET /api/prompts** — Lists all `.txt` prompts with `modified` flag (compares runtime vs default in `backend/data/prompts/`)
+- **GET /api/prompts/{name}** — Returns content, required variables, and modified flag
+- **PUT /api/prompts/{name}** — Saves modified content with min_length=10 validation, returns updated variables
+- **POST /api/prompts/{name}/reset** — Restores default content from `backend/data/prompts/`, returns 404 if no default exists
+
+Key implementation detail: PromptService is lazily initialized via `_get_prompt_service()` because `PROMPTS_PATH` is created during FastAPI's lifespan event, not at module import time.
+
+Router registered in `main.py` before the SPA catch-all mount.
+
+### Task 2: Frontend Prompt Editor (page, hooks, types, route, sidebar)
+- **Types**: Added `PromptInfo`, `PromptListResponse`, `PromptDetail` to `types.ts`
+- **Hooks**: Added `usePromptList`, `usePrompt`, `useSavePrompt`, `useResetPrompt` to `hooks.ts` with TanStack Query cache invalidation
+- **Page**: Created `PromptEditor.tsx` with two-column layout (1/3 list, 2/3 editor on lg, stacked on mobile)
+  - Prompt list with amber "Modificato" / stone "Default" badges
+  - Monospace textarea (min-height 400px, stone-900 bg)
+  - Live client-side variable extraction via regex `{{nome}}`
+  - Save button (amber, disabled when not dirty)
+  - Reset to Default with inline confirmation dialog
+  - Success/error feedback inline
+- **Route**: `/prompt-editor` added in `App.tsx`
+- **Sidebar**: "Prompt Editor" nav item with `Pencil` icon, positioned after "Genera Singolo Post" and before "Impostazioni"
+
+## Deviations from Plan
+
+### Auto-fixed Issues
+
+**1. [Rule 3 - Blocking] Lazy PromptService initialization**
+- **Found during:** Task 1
+- **Issue:** Module-level `PromptService(PROMPTS_PATH)` raised `FileNotFoundError` because `PROMPTS_PATH` directory doesn't exist at import time — it's created in the FastAPI lifespan event.
+- **Fix:** Changed to lazy initialization via `_get_prompt_service()` function with `PROMPTS_PATH.mkdir(parents=True, exist_ok=True)` on first access.
+- **Files modified:** `backend/routers/prompts.py`
+- **Commit:** 05972fa
+
+## Verification
+
+- [x] Backend imports without errors: `from backend.routers.prompts import router` OK
+- [x] 4 routes registered: `/api/prompts/`, `/api/prompts/{name}`, `/api/prompts/{name}`, `/api/prompts/{name}/reset`
+- [x] `main.py` includes `app.include_router(prompts.router)` before SPA catch-all
+- [x] TypeScript compiles with `npx tsc --noEmit` — zero errors
+- [x] Route `/prompt-editor` in App.tsx
+- [x] Sidebar contains "Prompt Editor" nav link
+- [x] Types and hooks exported correctly
+
+## Next Phase Readiness
+
+Plan 02-01 is complete. The Prompt Editor is functional for CRUD operations on prompt files. Plan 02-02 can proceed independently (Output Review enhancements).