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/route.sh

@@ -31,11 +31,22 @@ name=""
 # load-bearing for the flow's trigger comments: "@pm — @qa approved …" must route to @pm (pm is
 # checked first), while "@junior please address @qa's review …" must route to the dev (devs are
 # checked before qa). If you add an agent or reword a trigger in publish.sh, re-check this order.
+# WORD-BOUNDARY match, not substring: "@internal" or "x@internet.com" must NOT route to @intern
+# (the workflow gate can only do contains(), so this is where its false positives get filtered).
 for a in pm junior senior lead qa ops intern; do
-  case "$scan" in *"@$a"*) name=$a; break;; esac
+  if printf '%s' "$scan" | grep -qE "(^|[^[:alnum:]_])@$a([^[:alnum:]_-]|\$)"; then name=$a; break; fi
 done
 if [ -z "$name" ]; then
-  if [ -z "$CID" ]; then name=pm; else echo "no known agent mentioned"; exit 1; fi
+  if [ -z "$CID" ]; then
+    name=pm
+  else
+    # Not an agent task (e.g. the gate's contains() matched "@internal"). Skip GRACEFULLY: emit
+    # mode=skip so every later step no-ops — a red run for a non-agent comment is just noise.
+    echo "no known agent mentioned (word-boundary) — skipping run"
+    { echo "name=none"; echo "model=none"; echo "vision=false"; echo "mode=skip"; echo "skills=[]";
+      echo "branch=main"; echo "new=false"; echo "autopilot=false"; echo "issnum=$NUM"; } >> "$GITHUB_OUTPUT"
+    exit 0
+  fi
 fi
 model=$(jq -r --arg a "$name" '.[$a].model'  /tmp/agents.json)
 vision=$(jq -r --arg a "$name" '.[$a].vision' /tmp/agents.json)