Chameleon

The team-convention write paths now block-and-retry on a contended lock instead
of failing the capture outright.

Fixed

• Idiom and convention writes wait out a contended lock. /chameleon-teach,
  /chameleon-teach-competing-import (and its unteach), and the structured
  idiom-deprecation paths acquired their .idioms.lock / .conventions.lock
  non-blocking, so a capture that raced a second teach -- or, more commonly, the
  default-on background auto-refresh, which holds both locks across the whole
  7-36s re-derive -- failed immediately with "another operation holds the lock;
  retry shortly". They now block-and-retry for up to 10s, matching the sibling
  writers that already did (the refresh re-derive and the structured-teach
  helper). The .refresh.lock and .bootstrap.lock singletons stay non-blocking
  by design (a second concurrent refresh or bootstrap should fail fast, not
  queue). No data was ever lost -- the failure was clean -- but a capture no
  longer spuriously fails under the normal concurrency of a teach landing while
  auto-refresh runs.