Replace Clay with n8n, Ollama, SearXNG and browserless; add Telegram assistant

Remove the Clay role (Claude Code web UI) and its Anthropic API key.

New roles:
- ollama: local CPU LLM (qwen3:4b-instruct), internal network only
- browserless: headless Chromium for JavaScript-heavy pages
- searxng: metasearch backend for the chat web_search tool
- n8n at agent.ladkau.de: web chat (/chat), scheduled workflows,
  Telegram bot; workflows and credentials are imported from the repo

Telegram bot: Gemini 3.8 -> Gemini 3.5 -> local Qwen fallback chain,
/qwen to force the local model, /stocks and a weekday schedule
(07:30, 13:00, 17:40) for the MTE.DE / PTX.F stock report.

Also: dashboard and check-services entries for the chat, vault checks
for the new secrets (n8n, SearXNG, Gemini, Telegram, SMTP), updated
CLAUDE.md, runbooks and README.

ansible/roles/browserless/templates/docker-compose.yml.j2

@@ -0,0 +1,21 @@
+# Managed by Ansible — do not edit manually
+services:
+  browserless:
+    image: ghcr.io/browserless/chromium:{{ browserless_version }}
+    container_name: browserless
+    restart: unless-stopped
+    environment:
+      # One browser session at a time, short queue — keeps RAM use predictable on the shared VPS
+      CONCURRENT: "1"
+      QUEUED: "4"
+      TIMEOUT: "60000"
+    shm_size: 512m
+    mem_limit: {{ browserless_mem_limit }}
+    networks:
+      - browserless_internal
+
+# Not exposed via Traefik. Containers that need the API join this network
+# (declared as external there) and reach it at http://browserless:3000.
+networks:
+  browserless_internal:
+    name: browserless_internal