Add agentpr and watchpr CLI tools

agentpr manages PRs/comments/whoami as unkin-agent (Vault AppRole -> gitea creds
-> Gitea API), fixing tea's post-as-Ben default. watchpr polls PRs and alerts
only on merge/close, human comment, CI failure, or lost mergeability.

- cobra multi-binary layout mirroring node-lookup (cmd/ + internal/)
- Makefile (build, patch|minor|major, completions, rpm), nfpm RPM with both
  binaries + bash/zsh/fish completions, woodpecker CI publishing to rpm-internal
- unit tests for parsing, meaningful-change detection, and the Vault+Gitea client

.woodpecker/pre-commit.yaml

@@ -0,0 +1,18 @@
+when:
+  - event: pull_request
+
+steps:
+  - name: pre-commit
+    image: git.unkin.net/unkin/almalinux9-gobuilder:20260606
+    commands:
+      - uvx pre-commit run --all-files
+    backend_options:
+      kubernetes:
+        serviceAccountName: default
+        resources:
+          requests:
+            memory: 512Mi
+            cpu: 1
+          limits:
+            memory: 2Gi
+            cpu: 2