fix(tests): drop gexec Compiles spec — segfaults on GH Actions

[bborbe]

Summary

• The Compiles ginkgo spec spawned a child go build via gexec.Build from the race-instrumented test binary. On the Linux GH Actions runner this segfaults randomly (works locally; only repros on CI under -race).
• The spec was redundant: each test binary is itself package main, so if main.go does not compile, go test fails immediately.
• Removes the spec from all 6 affected main_test.go files (agent/claude, agent/code, agent/gemini, agent/pi + their cmd/run-task subdirs).

Test plan

• CI green on precommit (agent/code|pi|gemini|claude) matrix jobs

[ben-s-pull-request-reviewer]

PR Review Summary

Verdict: approve

This is a straightforward, well-reasoned change. The PR removes the gexec.Build Compiles specs from 6 test files across 4 agent services (claude, code, gemini, pi). The rationale is sound:

1. Redundancy: go test itself fails if main.go doesn't compile — the explicit assertion is unnecessary
2. CI flakiness: Spawning a child process from a race-instrumented binary segfaults on GH Actions Linux runners (works locally)
3. Well-documented: Each removal has a detailed NOTE explaining the rationale and referencing the vault document for full diagnosis

No issues found.

Must Fix: None

Should Fix: None

Nice to Have: None

---

{
  "verdict": "approve",
  "summary": "Clean removal of redundant gexec.Build Compiles specs across 6 test files. The specs were unnecessary since go test already fails if main.go doesn't compile, and their removal eliminates a known GH Actions segfault issue with race-instrumented child processes. Well-documented with clear rationale referencing the vault note.",
  "comments": [],
  "concerns_addressed": []
}

[ben-s-pull-request-reviewer]

Reviewed by ben-s-pull-request-reviewer[bot] — no concerns flagged.