chore(ci): remove stale and failing workflows

[Copilot]

Removes CI workflows that were obsolete, failing due to invalid credentials, or manually disabled without callers. Retains the reusable Zsh CI workflow and active metrics workflows.

• Pages publishing

  • Remove legacy GitHub Pages and asset publisher workflows.

• Metrics

  • Remove the failing activity-metrics schedule.

• Zsh validation

  • Remove the disabled legacy parser workflow; zsh-ci.yml remains the reusable implementation.

[Copilot]

Pull request overview

This PR removes several GitHub Actions workflows that are described as obsolete, failing, or unused, to simplify CI maintenance while keeping the reusable Zsh CI workflow and remaining metrics workflows.

Changes:

• Removed the legacy zsh-n.yml workflow (push/PR + workflow_call Zsh parsing/zcompile matrix).
• Removed legacy GitHub Pages and asset deployment workflows (gh-push.yml, gh-deploy-assets.yml).
• Removed the scheduled activity_metrics.yml workflow.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
.github/workflows/zsh-n.yml	Removed legacy Zsh zsh -n / zcompile workflow (previously ran on push/PR and supported workflow_call).
.github/workflows/gh-push.yml	Removed metrics-to-GitHub-Pages deploy workflow triggered via workflow_run.
.github/workflows/gh-deploy-assets.yml	Removed profile/** asset publishing workflow to GitHub Pages.
.github/workflows/activity_metrics.yml	Removed scheduled activity metrics workflow that used org-scoped credentials.

Suppressed comments (1)

.github/workflows/zsh-n.yml:1

• Deleting this workflow removes the only Zsh syntax validation that runs on push/PR in this repository. The repo still contains at least one .zsh file (.github/skills/new-zsh-plugin/templates/plugin.plugin.zsh), and no remaining workflow appears to call the reusable zsh-ci.yml, so Zsh templates can regress without CI catching it.

Consider either keeping a lightweight push/PR Zsh syntax workflow here, or adding a small caller workflow that uses: ./.github/workflows/zsh-ci.yml (optionally with run-zcompile: true) for paths that include .zsh templates.