feat(pm-agent): pin the first published agent-runner digest, start dry, and fix the token scopes

Rebased #61 onto the CI image pipeline (#81). This commit makes the remaining in-git
blockers to going live go away:

- deployment.yaml and PM_WORKER_IMAGE pin images run 340's digest (sha256:c4eba5b3...,
  tag sha-523cd9118f95 = main), read from the registry. Renovate markers unchanged.
- PM_DRY_RUN=true and PM_REQUIRE_LABEL=agent for the first run. Dry run is required, not
  just cautious: the run-340 image's baked worker template predates imagePullSecrets, so
  admission would deny its Jobs until CI re-publishes after this merge and Renovate bumps.
- Token scopes: Gitea 1.24.3 scopes GET /api/v1/user (the dispatcher's first call) under
  read:user. The documented list was missing it. Now read:user, write:repository,
  write:issue, read:package everywhere.
- Org-package read documented as a team (Packages=Read, no repos), not just a scope.
- sops is toolbox-only; the .examples say so and give the in-place edit.
- runbook: key-name check no longer emits Secret values before the pipe.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

platform/pm-agent/pm-agent-credentials.sops.yaml.example

@@ -60,11 +60,21 @@
 #     Keycloak service-account token therefore cannot authenticate to Gitea's API or to
 #     git-over-HTTP. Do not "upgrade" this to Keycloak without re-reading that.
 #
-#       Scopes: `write:repository` and `write:issue`. Nothing else — in particular NOT
-#       `write:admin`, NOT `write:organization`, NOT `write:user`.
+#       Scopes, exactly these four (one token serves both Secrets — see
+#       pm-agent-registry.sops.yaml.example):
+#         read:user         GET /user, the dispatcher's startup identity check. Gitea 1.24.3
+#                           puts the whole /api/v1/user group behind the `user` scope
+#                           category (routers/api/v1/api.go), so without it the dispatcher
+#                           CrashLoops on its first call even with an otherwise-valid token.
+#         write:repository  the clone, the branch push, the pull-request create, and the
+#                           dispatcher's reads of pulls/branches/commits.
+#         write:issue       reading open issues and posting issue comments.
+#         read:package      the kubelet's image pull (pm-agent-registry).
+#       Nothing else — in particular NOT `write:admin`, NOT `write:organization`, NOT
+#       `write:user`. (Until 2026-10-30 this list said two scopes; `read:user` was missing
+#       and `read:package` lived only in the registry template.)
 #
-#     `write:repository` covers the clone, the branch push and the pull-request create;
-#     `write:issue` covers reading and posting issue comments. (The repository's OTHER CI
+#     (The repository's OTHER CI
 #     token, `SETTINGS_API_TOKEN`, is a separate credential with `read:admin` — do not
 #     conflate them, and do not give this service that one. The 2026-10-02 measurement on
 #     PR #38 recorded in infra/gitea/approval-policy.json is about that token, not this one.)
@@ -94,6 +104,17 @@
 #
 # (4) COPY, FILL, ENCRYPT, COMMIT:
 #
+#     `sops` IS IN THE PINNED TOOLBOX, NOT ON THE HOST (measured 2026-10-30: absent from the
+#     workstation's PATH; sops 3.9.4 and vi in the toolbox). The simplest path needs no
+#     plaintext file at all — edit the committed, already-encrypted file in place, from a
+#     worktree, the way runbooks/vpn-remote-access.md does for its key:
+#
+#       ./infra/devcontainer/dev.sh run sops platform/pm-agent/pm-agent-credentials.sops.yaml
+#
+#     It opens vi on the decrypted document; replace the REPLACE-ME value(s), save, quit, and
+#     sops re-encrypts on write. If you take the cp route below instead, run the `sops -e -i`
+#     line through `./infra/devcontainer/dev.sh run` as well, and delete any plaintext temp file.
+#
 #       cp platform/pm-agent/pm-agent-credentials.sops.yaml.example \
 #          platform/pm-agent/pm-agent-credentials.sops.yaml
 #       $EDITOR platform/pm-agent/pm-agent-credentials.sops.yaml      # the two real values
@@ -120,7 +141,7 @@ metadata:
 type: Opaque
 stringData:
   # Gitea token for the dedicated, NON-ADMIN `pm-agent` account.
-  # Scopes: write:repository, write:issue.
+  # Scopes: read:user, write:repository, write:issue, read:package.
   gitea-token: REPLACE-ME-gitea-token
   # Output of `claude setup-token` on a subscription account. One year's validity.
   claude-code-oauth-token: REPLACE-ME-claude-code-oauth-token