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>

docker-compose.yml

@@ -0,0 +1,21 @@
+# Local dev / Coolify production
+# За local: docker compose up --build
+# За Coolify: качваш през git, Coolify сам пуска docker build + run
+version: '3.8'
+
+services:
+  webapp:
+    build: .
+    container_name: rip-help-webapp
+    environment:
+      # libpq формат (Postgres). Коригирай към твоя Postgres host.
+      HELP_DB_CONN: "host=192.168.88.18 port=5432 dbname=rip_help_system user=sa password=Parola~12345!!!"
+      OUTPUT_DIR: "/data/help_output"
+      HOME_IMAGE: "/data/help_output/Bairaci.png"
+    volumes:
+      # Картинките се очакват в OUTPUT_DIR/images/
+      # На сървъра ще качваш с WinSCP/rsync (напр. /home/sabo/share/help_output)
+      - ./data:/data/help_output:ro
+    ports:
+      - "8000:8000"
+    restart: unless-stopped