remove submit_doc_bug tool

The submit_doc_bug tool was modeled after the Zerto / Zoomin docs
backend pattern (anonymous JSON POST to a known feedback endpoint).
HVM docs use a different upstream feedback channel and the
team that owns them doesn't consume bug submissions through that
pipeline, so the tool would never be wired live here. Removing rather
than leaving a permanently-disabled stub keeps the MCP tool surface
clean (10 tools instead of 11) and the find_doc_inconsistencies
docstring now points operators at the docs portal's own feedback
channel for follow-up.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/docker-compose.yml

@@ -47,11 +47,6 @@ services:
       # Phase 10 — usage telemetry.
       USAGE_LOG_DIR: /app/var/logs
       USAGE_LOG_KEEP_DAYS: "90"
-
-      # Phase 12 — doc-bug submission gate. Off by default; on only
-      # in production after you've verified the endpoint contract.
-      DOC_BUG_SUBMIT_ENABLED: "false"
-      # DOC_BUG_API_URL: "https://docs-be.example.com/api/feedback"
     volumes:
       # Usage logs persist across container recreates.
       - ./hvm-docs-mcp-logs:/app/var/logs