Train hop automation

[nathan-barrett]

Adds a /trainhop orchestrator skill that walks through the full New Tab train-hop release workflow, with the following steps:

• Prompts the user to select which steps of the process they'd like to run
• Collects inputs that are needed for the selected steps
• Creates meta bug
• Updates locales
• update metrics
• generates the nimbus recipe
• File Jira QA ticket
• Create confluence page for that trainhop
• Bump minor version

All credentials are requested through python script, so separated from claude

Testing steps:

• Test in the firefox repo
• have firefox-aidev-plugins downloaded locally

1. Install the plugin: claude plugin marketplace add /path/to/firefox-aidev-plugins
2. Invoke /trainhop and verify the phase selection menu appears with options 1–4 before anything executes

[reemhamz]

issue: It seems that Claude did not know the following when running channel-metrics-diff:

“Finally, check the contents of browser/extensions/newtab/webext-glue/metrics to see if there is a runtime-metrics-N.json JSON file where N is a version less than what’s currently on the release channel. If so, that file can be deleted as part of this change”

Also, Claude stumbled several times while working and generating the metrics file. We should give it more specificity on what to expect and how to work around it.

Another thing, I've noticed that it is generating a metrics file with the wrong version number (if we’re trainhopping for 150, it generated a 149 file) you can take a look at that here – https://phabricator.services.mozilla.com/D286826

[suhaibmujahid]

@reemhamz any blocker here?