feat(pm-agent): an in-cluster AI Program Manager that turns Gitea issues into pull requests

A service that reads this repository's Gitea issues, decides what to do about each
thread as the Program Manager persona, and runs one worker agent per assignment that
authors a change, runs the merge gate and opens a pull request. It reacts to issue
creation and to comments; the assignment and all correspondence travel through the
issue thread and the PR. It authenticates with an Anthropic subscription token. It
never pushes to main and never merges.

Three choices carry the design, with alternatives recorded in docs/plans/:
 - it POLLS rather than receiving webhooks (Gitea's webhook SSRF guard, lost
   deliveries, and no inbound reach needed at all);
 - it keeps NO state: the trigger is "the newest thing in this thread was not
   written by me", so the issue thread is the state — no PVC, no backup obligation;
 - the model holds NO tools: its reply is one JSON object this code validates, so
   nothing in the path executes text.

The boundary is platform/kyverno/admission/pm-agent-job-shape.yaml (Enforce,
failurePolicy: Fail), not the RBAC: Kubernetes places no `use` check on
serviceAccountName, so "may create Jobs" is "may run arbitrary code as the
namespace's most privileged identity". Six rules admit only the committed shape, and
the worker identity is bound to nothing with no token mounted, so there is nothing to
escalate to. 28/28 offline Kyverno assertions.

Nothing has run: the image has never been built or pushed, and both the image digest
and the two credentials are deliberate placeholders. See the handoff entry's
"What I did NOT verify".

Refs CLAUDE.md §1/§3/§6, R-SEC-02, R-GITOPS-02.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

clusters/dev/kustomization.yaml

@@ -122,6 +122,25 @@ patches:
           provider: sops
           secretRef:
             name: sops-age
+  # pm-agent (the Program Manager agent service, clusters/base/pm-agent.yaml) carries
+  # pm-agent-credentials.sops.yaml — the Gitea write token for the dedicated non-admin bot
+  # account and the Anthropic subscription token from `claude setup-token`. Without this
+  # stanza kustomize hands Flux the raw SOPS document and the Secret applies full of
+  # ciphertext: the APPLY SUCCEEDS, and the only symptom is a dispatcher that cannot
+  # authenticate to Gitea — so this stanza is as load-bearing as the file it decrypts (same
+  # silent-failure shape as the apps-vms note below/above). The `sops-age` Secret is created
+  # out-of-band (name only).
+  - patch: |-
+      apiVersion: kustomize.toolkit.fluxcd.io/v1
+      kind: Kustomization
+      metadata:
+        name: pm-agent
+        namespace: flux-system
+      spec:
+        decryption:
+          provider: sops
+          secretRef:
+            name: sops-age
   # apps-vms (the KubeVirt VM tier, clusters/base/apps-vms.yaml) gained its FIRST encrypted Secret
   # on 2026-09-14: apps/vms/unifi/unifi-uos-installer.sops.yaml, the operator's UOS installer URL,
   # which 30-virtualmachine.yaml mounts into the guest as a disk. Without this stanza kustomize