Migrate to PostgreSQL + add FastAPI webapp for Coolify deploy

Backend migration:
- Replace pyodbc/SQL Server with psycopg2/PostgreSQL throughout
- Rewrite Database class with portable SQL: SERIAL, ON CONFLICT, NOW()
- Lowercase table names (rip_help_files, rip_help_sections) - Postgres convention
- libpq connection string format in HELP_DB_CONN

Webapp (webapp/):
- FastAPI app: GET /, GET /images/<f>, GET /home-image, GET /api/sections,
  POST /api/keywords/<code>, GET /healthz
- Jinja2 template extracted from generate_html.py with HTTP image URLs
- Direct keyword save to DB (no JSON download detour)
- Same prefix scoping as CLI tools (?prefix=RIP)

Deployment:
- Dockerfile (python:3.12-slim + uvicorn)
- docker-compose.yml for local dev
- requirements-webapp.txt (minimal, no Windows-only deps)
- .dockerignore excludes pipeline scripts and BAT files
- README updated with webapp section and Coolify deploy guide

Also: switch AI model to claude-haiku-4-5 (~3x cheaper, same quality for this task)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -120,5 +120,65 @@ UNIQUE constraint: `(prefix, file_path)`
 |---|---|---|
 | `MIN_SECTION_TOKENS` | 60 | Под този праг секцията се слива с предишната |
 | `MAX_AI_CHARS` | 4000 | Символи, пращани към Claude |
-| `AI_MODEL` | claude-sonnet-4-6 | Модел за класификация |
+| `AI_MODEL` | claude-haiku-4-5 | Модел за класификация |
 | `MIN_IMAGE_PX` | 50 | Картинки под NxN px се пропускат |
+
+---
+
+## Webapp (FastAPI)
+
+`webapp/` съдържа FastAPI app за server deploy (Coolify / Docker).
+
+### Endpoint-и
+
+| Метод | Път | Описание |
+|---|---|---|
+| GET | `/` | HTML viewer (Home/Editor/Search/Generator); query `?prefix=RIP&home=1` |
+| GET | `/images/<file>` | Сервира картинка от `OUTPUT_DIR/images/` |
+| GET | `/home-image` | Home image (от `HOME_IMAGE` env var или `Bairaci.png`) |
+| GET | `/api/sections` | JSON списък със секции; query `?prefix=` |
+| POST | `/api/keywords/<code>` | `{keywords: "..."}` → UPDATE в DB |
+| GET | `/healthz` | Health check (DB ping) |
+
+### Env vars
+
+| Var | Default | Описание |
+|---|---|---|
+| `HELP_DB_CONN` | — | libpq формат за Postgres (задължително) |
+| `OUTPUT_DIR` | `./data` | Директория с `images/` подпапка |
+| `HOME_IMAGE` | — | Абсолютен път към home картинка (опционален) |
+
+### Локален dev
+
+```
+pip install -r requirements-webapp.txt
+$env:HELP_DB_CONN="host=192.168.88.18 port=5432 dbname=rip_help_system user=sa password=..."
+$env:OUTPUT_DIR="q:\RIP_Help_Source\Output"
+python -m uvicorn webapp.main:app --reload
+# отвори http://127.0.0.1:8000/?prefix=RIP&home=1
+```
+
+### Coolify deploy
+
+1. В Coolify: New Resource → Application → Public/Private Repository
+2. URL: `https://git.inex-project.net/sabo/rip-help-system.git`
+3. Build pack: **Dockerfile**
+4. Environment variables (в Coolify UI, не в git):
+   - `HELP_DB_CONN=host=... port=5432 dbname=rip_help_system user=... password=...`
+   - `OUTPUT_DIR=/data/help_output`
+   - `HOME_IMAGE=/data/help_output/Bairaci.png` (по избор)
+5. Persistent storage (volume): `/data/help_output` (там качваш картинките с WinSCP/rsync)
+6. Port: 8000
+7. Custom domain → Coolify прави HTTPS (Let's Encrypt) автоматично
+
+### Качване на картинки на сървъра
+
+Локалният `help_processor.py` пише в `q:\RIP_Help_Source\Output\` (включително `images/` подпапка). За deploy:
+
+```
+# с WinSCP — sync на цялата директория
+local:  q:\RIP_Help_Source\Output\
+remote: /home/sabo/share/help_output/   ← Coolify volume mount
+```
+
+Базата (Postgres на 192.168.88.18) се ползва от webapp-а директно.