agents: per-agent Gitea identity — each agent uses its own token

Drop the shared AGENT_TOKEN as the primary credential; every agent now acts
as its own Gitea user (TOKEN_PM for @pm, TOKEN_OPS for @ops, …) for API
calls, delegation/autopilot trigger comments, and PR merges.

- agent.yml: Run-agent step injects SELF_TOKEN — a ternary selecting the
  running agent's own token by name, falling back to AGENT_TOKEN for repos
  not yet migrated to per-agent tokens (e.g. homelab). Only that one token
  enters the agent process, so no agent can act as another. The gitea-api /
  gitea-admin skill-setup steps no longer carry a token (they only write docs).
- Gate: trust the agent roster (pm/junior/senior/lead/qa/ops) as comment
  authors so an agent's own delegation/autopilot trigger comment (posted with
  its PAT, no 🤖 prefix) fires the next run. @ops added to the mention set.
- publish.sh: TOK = agent identity (comments/replies); new TTOK = trigger/merge
  token (agent PAT, else AGENT_TOKEN fallback) for delegation, autopilot @qa
  triggers, and PR merges that must fire downstream workflows.
- skill-gitea-api.sh / skill-gitea-admin.sh / run-agent.sh: AGENT_TOKEN/
  TOKEN_OPS → SELF_TOKEN in the emitted skill docs and env contract.

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

.gitea/workflows/scripts/run-agent.sh

@@ -3,7 +3,7 @@
 # plain-text reply (/tmp/agent_out.md) plus the raw event stream (/tmp/events.jsonl).
 #
 # Required env (provided by the workflow step):
-#   ANTHROPIC_API_KEY AGENT_TOKEN NAME MODEL VISION MODE HAS_IMAGES BRANCH AUTOPILOT NUM TITLE
+#   ANTHROPIC_API_KEY SELF_TOKEN NAME MODEL VISION MODE HAS_IMAGES BRANCH AUTOPILOT NUM TITLE
 #   IBODY CMT
 #   FILES   (the opencode -f image flags, from the imgs step output)
 #   AUTOPILOT is 'true' when the issue carries the `autopilot` label (label-gated autopilot mode).