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

packaging/nfpm.yaml

@@ -0,0 +1,64 @@
+---
+# nfpm config for building the agent-tools RPM.
+# Rendered through envsubst (see scripts/build-rpm.sh) then fed to `nfpm pkg`.
+
+name: ${PACKAGE_NAME}
+version: ${PACKAGE_VERSION}
+release: ${PACKAGE_RELEASE}
+arch: ${PACKAGE_ARCH}
+platform: ${PACKAGE_PLATFORM}
+section: default
+priority: extra
+description: "${PACKAGE_DESCRIPTION}"
+
+maintainer: ${PACKAGE_MAINTAINER}
+homepage: ${PACKAGE_HOMEPAGE}
+license: ${PACKAGE_LICENSE}
+
+disable_globbing: false
+
+replaces:
+  - agent-tools
+provides:
+  - agent-tools
+
+contents:
+  # The CLI binaries.
+  - src: dist/agentpr
+    dst: /usr/bin/agentpr
+    file_info:
+      mode: 0755
+      owner: root
+      group: root
+  - src: dist/watchpr
+    dst: /usr/bin/watchpr
+    file_info:
+      mode: 0755
+      owner: root
+      group: root
+
+  # Shell completions (generated by scripts/build-rpm.sh before packaging).
+  - src: dist/completions/agentpr.bash
+    dst: /usr/share/bash-completion/completions/agentpr
+    file_info:
+      mode: 0644
+  - src: dist/completions/_agentpr
+    dst: /usr/share/zsh/site-functions/_agentpr
+    file_info:
+      mode: 0644
+  - src: dist/completions/agentpr.fish
+    dst: /usr/share/fish/vendor_completions.d/agentpr.fish
+    file_info:
+      mode: 0644
+  - src: dist/completions/watchpr.bash
+    dst: /usr/share/bash-completion/completions/watchpr
+    file_info:
+      mode: 0644
+  - src: dist/completions/_watchpr
+    dst: /usr/share/zsh/site-functions/_watchpr
+    file_info:
+      mode: 0644
+  - src: dist/completions/watchpr.fish
+    dst: /usr/share/fish/vendor_completions.d/watchpr.fish
+    file_info:
+      mode: 0644