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>

generate_html.py

@@ -11,16 +11,13 @@ from datetime import datetime
 from typing import Optional
 
 try:
-    import pyodbc
+    import psycopg2
 except ImportError:
-    sys.exit("Инсталирай pyodbc:  pip install pyodbc")
+    sys.exit("Инсталирай psycopg2:  pip install psycopg2-binary")
 
 CONN_STR = os.getenv(
     "HELP_DB_CONN",
-    "DRIVER={ODBC Driver 18 for SQL Server};"
-    "TrustServerCertificate=yes;"
-    "SERVER=94.26.63.238,13151;DATABASE=blondina;"
-    "UID=blondina_login;PWD=blondina_parola_123"
+    "host=192.168.88.18 port=5432 dbname=rip_help_system user=sa password=Parola~12345!!!"
 )
 OUT_HTML = Path(__file__).parent / "help_viewer.html"
 
@@ -80,26 +77,26 @@ def _rich_html_with_images(html: str, output_dir: Path, embed: bool = False) ->
 
 
 def fetch_sections(prefix: Optional[str] = None):
-    conn = pyodbc.connect(CONN_STR, autocommit=True)
+    conn = psycopg2.connect(CONN_STR)
     cur  = conn.cursor()
     if prefix:
         cur.execute("""
             SELECT s.prefix, s.code, s.title, s.keywords, s.char_count,
                    s.source_file, s.output_path, s.updated_at,
                    s.images, s.html_text, f.section_count
-            FROM   RIP_help_sections s
-            LEFT JOIN RIP_help_files f
+            FROM   rip_help_sections s
+            LEFT JOIN rip_help_files f
               ON f.file_path = s.source_file AND f.prefix = s.prefix
-            WHERE  s.prefix = ?
+            WHERE  s.prefix = %s
             ORDER  BY s.code
-        """, prefix)
+        """, (prefix,))
     else:
         cur.execute("""
             SELECT s.prefix, s.code, s.title, s.keywords, s.char_count,
                    s.source_file, s.output_path, s.updated_at,
                    s.images, s.html_text, f.section_count
-            FROM   RIP_help_sections s
-            LEFT JOIN RIP_help_files f
+            FROM   rip_help_sections s
+            LEFT JOIN rip_help_files f
               ON f.file_path = s.source_file AND f.prefix = s.prefix
             ORDER  BY s.prefix, s.code
         """)