Bump zot registry to v2.1.15 (#293)

## Summary
- Upgrade zot OCI registry from v2.1.13 to v2.1.15 on indri
- Addresses CVE-2025-30204 (golang-jwt memory) and open redirect via callback_ui
- No config template changes needed (externalUrl is auto-allowlisted)
- Requires Go 1.25.7 (bump from 1.25.6 via mise)

## Data Safety
- Data directory ~/erichblume/zot is NOT touched during build or deploy
- No schema migrations in v2.1.14 or v2.1.15
- Storage format remains OCI spec 1.1.0

## Deployment Steps
- [ ] SSH to indri: bump Go to 1.25.7 via `mise use go@1.25.7`
- [ ] Fetch and checkout v2.1.15 in ~/code/3rd/zot
- [ ] Build: `mise x -- make binary`
- [ ] Restart LaunchAgent
- [ ] Verify: `curl -s http://localhost:5050/v2/` returns 200
- [ ] Verify: `curl -s https://registry.ops.eblu.me/v2/_catalog` lists repos
- [ ] Verify: `mise run services-check`

Reviewed-on: #293

ansible/roles/zot/templates/zot.plist.j2

@@ -16,6 +16,11 @@
 	<true/>
 	<key>KeepAlive</key>
 	<true/>
+	<key>EnvironmentVariables</key>
+	<dict>
+		<key>PATH</key>
+		<string>/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin</string>
+	</dict>
 	<key>StandardOutPath</key>
 	<string>{{ zot_log_dir }}/mcquack.zot.out.log</string>
 	<key>StandardErrorPath</key>