feat: Add SearXNG for improved web search

- Add SearXNG service to docker-compose.yml (port 11112)
- Add SEARXNG_SECRET_KEY to .env.example
- Add searxng-data/settings.yml with FR engines (google, bing, ddg, qwant)
- Add docs/SEARXNG-INTEGRATION.md with OpenWebUI tool setup

searxng-data/settings.yml

@@ -0,0 +1,60 @@
+# ═══════════════════════════════════════════════════════════
+# EFFI SEARXNG - Meta-search Engine Configuration
+# Instance: effi-server (192.168.1.27)
+# ═══════════════════════════════════════════════════════════
+
+use_default_settings: true
+
+general:
+  instance_name: "Effi Search"
+  privacypolicy_url: false
+  donation_url: false
+  contact_url: false
+  enable_metrics: false
+
+search:
+  format: "json"
+  max_results: 15
+  default_lang: "fr"
+  formats:
+    - html
+    - json
+
+engines:
+  - name: google
+    engine: google
+    language: fr
+  - name: bing
+    engine: bing
+    language: fr-FR
+  - name: duckduckgo
+    engine: duckduckgo
+    language: fr-FR
+  - name: qwant
+    engine: qwant
+    language: fr
+  - name: wikipedia
+    engine: wikipedia
+    language: fr
+
+server:
+  secret_key: "${SEARXNG_SECRET_KEY}"
+  bind_address: "0.0.0.0"
+  port: 8080
+  limiter: false
+  public_instance: false
+
+ui:
+  default_theme: simple
+  static_use_hash: true
+  default_view: index
+  results_on_new_tab: false
+
+outgoing:
+  request_timeout: 10.0
+  useragent_suffix: ""
+  pool_connections: 100
+  pool_maxsize: 20
+
+enable_obfuscation: false
+enable_http2: true