Fix HOME volume mount, genericize topic, add progress statuses, extract lexicon

- Volume was mounted at ~/.claude only, but claude-code writes auth to
  ~/.claude.json too — that file lived on the ephemeral container layer and
  was lost on every recreate. Now the whole $HOME is on the named volume,
  and claude-config moved outside HOME (/app) so it isn't shadowed by it.
- Default /news topic was hardcoded to AI; now it's a configurable
  DEFAULT_TOPIC (plain "главные новости дня"), topic is fully free-form.
- Prompt now instructs Claude to send interim "⏳ ..." progress updates via
  send_to_telegram while researching, not just the final digest — a bare
  request like "call this tool" was already taking 3+ minutes end-to-end,
  so silence read as broken.
- All user-facing/prompt text moved into bot/lib/lexicon.dart.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docker-compose.yml

@@ -5,7 +5,7 @@ services:
       dockerfile: runner/Dockerfile
     env_file: .env
     volumes:
-      - claude-home:/home/agent/.claude
+      - claude-home:/home/agent
     restart: unless-stopped
 
 volumes: