feat(chat): integrate chat project into monorepo with full app structure

- Restructure chat as apps/mobile, apps/web, apps/landing, backend
- Add NestJS backend for secure Azure OpenAI API calls
- Remove exposed API key from mobile app (security fix)
- Add shared chat-types package
- Create SvelteKit web app scaffold
- Create Astro landing page scaffold
- Update pnpm workspace configuration
- Add project-level CLAUDE.md documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

chat/apps/mobile/scripts/setup_supabase_functions.sql

@@ -0,0 +1,52 @@
+-- Erstelle eine Funktion zum Ausführen von SQL-Abfragen
+CREATE OR REPLACE FUNCTION execute_sql(query text)
+RETURNS JSONB
+LANGUAGE plpgsql
+SECURITY DEFINER
+AS $$
+DECLARE
+  result JSONB;
+BEGIN
+  EXECUTE 'SELECT jsonb_agg(row_to_json(t)) FROM (' || query || ') t' INTO result;
+  RETURN COALESCE(result, '[]'::jsonb);
+EXCEPTION
+  WHEN OTHERS THEN
+    RAISE EXCEPTION 'SQL-Fehler: %', SQLERRM;
+END;
+$$;
+
+-- Erstelle eine Funktion zum Erstellen der models-Tabelle, falls sie nicht existiert
+CREATE OR REPLACE FUNCTION create_models_table()
+RETURNS VOID
+LANGUAGE plpgsql
+SECURITY DEFINER
+AS $$
+BEGIN
+  -- Prüfe, ob die Tabelle bereits existiert
+  IF NOT EXISTS (
+    SELECT FROM information_schema.tables 
+    WHERE table_schema = 'public' 
+    AND table_name = 'models'
+  ) THEN
+    -- Erstelle die Tabelle
+    CREATE TABLE models (
+      id UUID PRIMARY KEY,
+      name TEXT NOT NULL,
+      description TEXT,
+      parameters JSONB,
+      created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+      updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+    );
+    
+    -- Erstelle einen Trigger für updated_at
+    CREATE TRIGGER set_updated_at
+    BEFORE UPDATE ON models
+    FOR EACH ROW
+    EXECUTE FUNCTION set_updated_at();
+    
+    RAISE NOTICE 'Tabelle models wurde erstellt.';
+  ELSE
+    RAISE NOTICE 'Tabelle models existiert bereits.';
+  END IF;
+END;
+$$;