Fix smoke tests: Install Go runtime for Serena testing

[Copilot]

Smoke test workflows failed with go: command not found when testing Serena tool functionality. The serena.languages.go configuration only enables Serena's Go language server—it doesn't install Go on the runner.

Changes

Added explicit Go runtime installation to smoke test workflows:

serena:
  languages:
    go: {}
runtimes:
  go:
    version: "1.25"

Files Modified

• .github/workflows/smoke-copilot.md
• .github/workflows/smoke-claude.md
• .github/workflows/smoke-codex.md
• Regenerated corresponding .lock.yml files

The Go runtime now installs via actions/setup-go before agent execution, making go version available for Serena testing validation.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Smoke Test: Copilot - 21157819280</issue_title>
<issue_description>## Smoke Test Results

Run: https://github.com/githubnext/gh-aw/actions/runs/21157819280
Status: ❌ FAIL (1 of 5 tests failed)
Timestamp: 2026-01-20T02:55:27Z

Test Results

Test	Result
GitHub MCP	✅ Retrieved last 2 merged PRs
Serena Go	❌ go: command not found
Playwright	✅ Navigated to GitHub, verified title
File Writing	✅ Created test file
Bash Tool	✅ Verified file with cat

GitHub MCP Test

• PR [WIP] Fix lint-go failure after PR #10756 merge #10777: [WIP] Fix lint-go failure after PR Add test coverage for compiler core files (2,291 untested lines) #10756 merge
• PR Remove unused hasInternalPrefix function causing lint failure #10774: Remove unused hasInternalPrefix function causing lint failure

Playwright Test

Page Title: "GitHub · Change is constant. GitHub keeps you ahead. · GitHub"

File Test

Path: /tmp/gh-aw/agent/smoke-test-copilot-21157819280.txt
Content: Smoke test passed for Copilot at Tue Jan 20 02:55:27 UTC 2026

Failure Details

Serena Go Test: bash: go: command not found (exit code 127)

PR Context

Author: @copilot
Assignees: @pelikhan, @copilot

AI generated by Smoke Copilot for #10776

• expires on Jan 20, 2026, 4:57 AM UTC

Comments on the Issue (you are @copilot in this section)

• Fixes Smoke Test: Copilot - 21157819280 #10781

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