ci(gadfly): trim the weakest reviewers from the swarm

Drop the four lowest-graded reviewers — m5/qwen3.6:35b-mlx, gemma4:cloud,
gpt-oss:120b-cloud, kimi-k2.7-code:cloud. Removing m5/qwen3.6 takes the last
local Mac out, so this is now a cloud-only fleet of 6 ollama-cloud models;
GADFLY_ENDPOINT_M5 and the m5 concurrency entry are gone and the per-job timeout
drops to 45m. README/CLAUDE.md kept in sync.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -141,9 +141,9 @@ Ship work through PRs and let Gadfly review it before merge:
 
 - **Push to a PR, never straight to `main`.** Branch, push, open a PR.
   `.gitea/workflows/adversarial-review.yml` runs Gadfly (the standalone
-  agentic adversarial reviewer) — a fleet of 9 ollama-cloud models +
-  the M5 Mac via foreman, each running the 3-lens suite (security,
-  correctness, error-handling). Advisory only; it never blocks the merge.
+  agentic adversarial reviewer) — a fleet of 6 ollama-cloud models, each
+  running the 3-lens suite (security, correctness, error-handling). Advisory
+  only; it never blocks the merge.
 - **Wait for Gadfly to finish, then read its output.** Don't merge while the
   review is still running. Each model posts one consolidated comment; weigh
   every finding on its merits and fix the real ones (Gadfly is a simple