docs(discovery): amend the rollout plan after the Fox review

Most of the Fox review's findings traced back to this plan's text, so:

- Global Constraints gain the reporter rules it surfaced: call
  refresh_discovery() before automatic_config(); set inverter_type with
  automatic_config()'s own predicate; fixtures from real samples, units
  included; evidence numbers must distinguish the cases they claim to;
  a validate_report() round trip per reporter; site names never in
  info; the spec's capability tokens; firmware in info; comments cite
  symbols, not line numbers.
- A dated Amendments entry records each change and why, including the
  corrected reasoning for Fox and GE Cloud carrying no entity map.
- Task 4's Interfaces line no longer claims it consumes
  discovery_entities(), and its Background, Step 5 placement, mutation
  checks, code block and test block are regenerated from the code as it
  stands.
- Subsequent plans record that entity maps are a decision needed before
  Plan 2, and the vocabulary note uses Fox's current tokens.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: CI