fix(phase-complete): keep internal phase diagnostics out of chat-visible output

[Copilot]

Summary

• Removes console.warn/console.info/console.error from non-fatal diagnostic paths in executePhaseComplete — fixes issue fix(guardrails): recover from provider outages #875 where internal phase-boundary messages leaked into the OpenCode chat bar
• Routes gate-skip notifications to the tool result warnings array (operator-visible, structured) and lock-release failures to the debug-gated logger (OPENCODE_SWARM_DEBUG=1)
• Adds two regression tests asserting no console writes occur on turbo-mode and non-code drift-skip paths

Invariant audit

• 1 (plugin init): not touched — no init path changes; phase-complete runs post-init
• 2 (runtime portability): touched — dist/ rebuilt; node --input-type=module -e "await import('./dist/index.js')" → dist import OK
• 3 (subprocesses): not touched — grep of changed source files shows no new spawn call sites
• 4 (.swarm containment): not touched — no .swarm/ path changes
• 5 (plan durability): not touched — no plan schema changes
• 6 (test_runner safety): not touched — no test_runner changes
• 7 (test writing): touched — two new bun:test regression tests with finally-block console restore; no mock.module usage; all 52 phase-complete tests pass
• 8 (session state): not touched — no session state changes
• 9 (guardrails/retry): not touched — no retry logic changes
• 10 (chat/system msg): touched — grep src/tools/phase-complete.ts 'console\.(warn|info|error)' returns zero matches; fix removes the invariant violation
• 11 (tool registration): not touched — no tool registration changes
• 12 (release/cache): touched — docs/releases/v7.20.2.md created (v7.20.1 was already claimed by release-please for chore(main): release 7.20.1 #877); package.json/CHANGELOG/.release-please-manifest.json untouched

Test plan

• bun --smol test tests/unit/tools/phase-complete.test.ts — 52 pass, 0 fail
• All tests/unit/tools/*.test.ts per-file — phase-complete suite fully green; other failures confirmed pre-existing on clean main
• bunx biome ci . — 0 errors, 2 pre-existing warnings (unrelated file)
• bun run typecheck — clean
• bun test tests/security — 139/139 pass
• bun test tests/smoke — 10/10 pass
• node scripts/repro-704.mjs — 3/3 OK (plugin init deadline)
• node --input-type=module -e "await import('./dist/index.js')" → dist import OK
• dist/ rebuilt from source and committed; no drift

Pre-existing failures

Tiers 2–4 contain pre-existing failures confirmed on clean main checkout (worktree verify):
diagnostic-gating (3), phase-complete-lean-turbo-critic (9), phase-complete-lean-turbo-reviewer (7), sast-and-cochanger-tools (18), tool-registration-conformance (1), update-task-status.gate-fix (4), integration/phase-completion-e2e (subset), adversarial (10). None in files touched by this PR.

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Original Copilot description

phase_complete was emitting internal phase-boundary diagnostics through raw console output, which can surface in the OpenCode chat bar. This change keeps those messages in structured tool output or debug-only logging instead of leaking workflow internals into the user conversation.

• What changed

  • Removed chat-visible console.warn / console.info / console.error usage from src/tools/phase-complete.ts for non-fatal internal diagnostics.
  • Routed non-blocking diagnostic paths through the existing debug-gated logger.
  • Kept operator-relevant information in the tool response warnings array where it belongs.

• Behavior changes

  • Turbo-mode gate skips are now reported as structured warnings on the phase_complete result instead of console output.
  • Non-code / disabled drift-check skip messages stay visible to the caller via warnings, without writing to the chat-visible console path.
  • Lock-release cleanup failures are downgraded to non-fatal debug logging instead of raw console error output.

• Regression coverage

  • Added focused tests to assert that:
    • turbo-mode phase completion returns warnings without writing to console.warn / console.error
    • non-code drift-skip paths return warnings without writing to console.info