agents: review round 2 — split-PR flow, thread recency, mention boundaries, learnings cap, pm model

- publish.sh: resolve_prs matches ai/issue-N AND ai/issue-N-<slug> split branches
  (exact-only silently stalled DELEGATE:@qa and autopilot MERGE_PR on slugged
  work); qa hand-off lists all open PRs; autopilot refuses to merge multi-PR
  issues (drops the label, hands to the human) — merging one of several open
  PRs is half a change deployed. Retro's state=all resolve matches slugs too.
- fetch-thread.sh: paginate and keep the NEWEST 100 comments — a bare limit=100
  kept the OLDEST page and dropped recent decisions on long threads.
- route.sh: word-boundary mention matching ("@internal" no longer routes to
  @intern); a comment with no real agent mention now SKIPS gracefully
  (mode=skip outputs + step guards in agent.yml) instead of a red run.
- run-agent.sh: LEARNINGS.md cap is line-aware and keeps the NEWEST entries
  (retros append at the bottom; the old head -c cut the latest lessons first).
- agents.json/README: @pm gemma4 -> minimax-m3 — the retro rule demands an
  investigating PM, and gemma4 posted 0 tool calls on every run; minimax is the
  model @qa demonstrably uses tools with.
- agent.yml: document the PR-thread concurrency-group caveat.

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

.gitea/workflows/scripts/agents.json

@@ -1,6 +1,6 @@
 {
   "pm": {
-    "model": "ollama-cloud/gemma4:cloud",
+    "model": "ollama-cloud/minimax-m3:cloud",
     "vision": true,
     "mode": "comment",
     "skills": [