Adds explicit routing bias in two surfaces so both operators (README)
and downstream LLMs consuming the MCP tools (server.js tool
descriptions) pick up the same framing:

- Weak-tier is the DEFAULT for a reason: most atomic work (edits,
  refactors, summaries, glue, well-scoped fixes) gets the same correct
  answer from a Gemini Flash / Groq / DeepSeek / :free model as from
  Claude Opus or Codex Pro, in a fraction of the time.
- Strong-tier reserved for tasks that actually need frontier: multi-step
  debug, architecture, novel algorithms, ambiguous requirements.
- escalate_to_pro is a retry lever, not a default. When weak fails, first
  ask if the SPEC was ambiguous — sharpening the prompt beats spending
  more compute.

pick_agents and dispatch MCP tool descriptions now carry the same
message in schema, so any LLM caller reading the tool contract at
runtime inherits the routing bias automatically.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>