feat(artifact): add direct log artifact upload to action runtime

[marcusrbrown]

Summary

• Move OpenCode log artifact upload from workflow YAML steps (actions/upload-artifact) into the action's TypeScript runtime
• When OPENCODE_PROMPT_ARTIFACT is enabled, the action automatically uploads ~/.local/share/opencode/log as a GitHub artifact — consumers no longer need a separate upload-artifact workflow step
• Artifact naming follows the existing pattern: opencode-logs-{runId}-{runAttempt}

Changes

New: src/services/artifact/ (Layer 1)

• upload.ts — uploadLogArtifact() wrapping @actions/artifact DefaultArtifactClient. Collects files via fs.readdir({recursive: true}), uploads with 7-day retention and max compression. Non-fatal on failure.
• index.ts — Re-exports

Modified: Harness (Layer 3)

• cleanup.ts — Uploads artifacts after cache save when OPENCODE_PROMPT_ARTIFACT is set; writes ARTIFACT_UPLOADED state on success
• post.ts — Fallback artifact upload in post-action hook if cleanup didn't complete it (mirrors the cache save double-write pattern)
• state-keys.ts — Added ARTIFACT_UPLOADED state key for main↔post handoff

Modified: Shared (Layer 0)

• env.ts — Added getGitHubRunAttempt() with Number.isFinite() guard against NaN/negative values

Modified: Workflows

• fro-bot.yaml / ci.yaml — Removed actions/upload-artifact steps (replaced by in-action upload)

New dependency

• @actions/artifact@6.2.1 — bundled by tsdown via existing @actions/* rule

How it works

1. execution.ts writes prompt artifact to log dir when OPENCODE_PROMPT_ARTIFACT=true (existing, unchanged)
2. Cleanup phase (main action finally block) uploads the log directory as a GitHub artifact
3. Post-action hook checks ARTIFACT_UPLOADED state — uploads only if cleanup didn't complete it
4. Both paths are non-fatal: upload failures log warnings but never crash the action

Test coverage

• upload.test.ts (6 tests) — dir missing, empty dir, upload success/failure, custom options, directory entry filtering
• env.test.ts (6 new) — getGitHubRunAttempt with valid, missing, empty, non-numeric, zero, negative values
• post.test.ts (4 new) — artifact upload enabled+not-yet-uploaded, already-uploaded skip, disabled skip, non-fatal failure
• state-keys.test.ts (2 updated) — new key + count

1085 tests pass, 0 lint errors, type-check clean, dist in sync.

[fro-bot]

Review Summary

This PR demonstrates excellent adherence to established codebase patterns. The implementation is well-structured with comprehensive test coverage.

Architecture & Design ✓

• Layer placement: New services/artifact/ module correctly positioned as Layer 1 (services layer)
• Double-write pattern: Post-action fallback mirrors the existing cache save pattern (STATE_KEYS.CACHE_SAVED → STATE_KEYS.ARTIFACT_UPLOADED)
• Non-fatal error handling: Both upload paths gracefully degrade with warnings, never crashing the action

Code Quality ✓

• Logger injection: All functions properly inject logger
• Functional style: No classes, only pure functions
• ESM imports: .js extensions correctly used
• Strict booleans: Explicit comparisons (=== 'true', !== 'true') not implicit falsy
• Guard conditions: getGitHubRunAttempt() uses Number.isFinite() and guards against zero/negative values

Test Coverage ✓

6 new tests in upload.test.ts + 4 new tests in post.test.ts + 6 new tests in env.test.ts:

• Missing directory handling
• Empty directory handling
• Upload success/failure paths
• Custom options passthrough
• Directory entry filtering (files vs directories)
• State key verification

Implementation Details ✓

1. upload.ts: Clean implementation with graceful handling of missing/empty directories
2. cleanup.ts: Correctly uploads after cache save when OPENCODE_PROMPT_ARTIFACT is enabled
3. post.ts: Fallback upload via state check mirrors cache save pattern
4. getGitHubRunAttempt(): Returns 1 for invalid/missing/zero/negative values (correct default)

Bundling ✓

@actions/artifact@6.2.1 correctly bundled via existing noExternal rule for @actions/* packages (line 172 in tsdown.config.ts).

Verification ✓

• 1085 tests pass
• Type check clean
• Lint clean (34 warnings are pre-existing, none in new code)
• Dist in sync

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No blocking issues found. The implementation is production-ready.

Run Summary

Field	Value
Event	pull_request
Repository	fro-bot/agent
Run ID	23692874135
Cache	hit
Session	ses_2ca067d11ffe5emqJuH27wRBgb