fix(zeroclaw): remove broken zeroclaw agent (repo 404) (#3107)

* fix(zeroclaw): remove broken zeroclaw agent (repo 404)

The zeroclaw-labs/zeroclaw GitHub repository returns 404 — all installs
fail. Remove zeroclaw entirely from the matrix: agent definition,
setup code, shell scripts, e2e tests, packer config, skill files,
and documentation.

Fixes #3102

Agent: code-health
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* fix(zeroclaw): remove stale zeroclaw reference from discovery.md ARM agents list

Addresses security review on PR #3107 — the last remaining zeroclaw
reference in .claude/rules/discovery.md is now removed.

Agent: issue-fixer
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* fix(zeroclaw): remove remaining stale zeroclaw references from CI/packer

Remove zeroclaw from:
- .github/workflows/agent-tarballs.yml ARM build matrix
- .github/workflows/docker.yml agent matrix
- packer/digitalocean.pkr.hcl comment
- sh/e2e/e2e.sh comment

Addresses all 5 stale references flagged in security review of PR #3107.

Agent: issue-fixer
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

---------

Co-authored-by: B <6723574+louisgv@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

.github/workflows/docker.yml

@@ -20,7 +20,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        agent: [claude, codex, cursor, openclaw, opencode, kilocode, zeroclaw, hermes, junie]
+        agent: [claude, codex, cursor, openclaw, opencode, kilocode, hermes, junie]
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5  # v4