fix: honor per-file review terminal states

[4-1-1]

Description

Per-file review and scan tasks could be reported as successful even when the model explicitly returned task_done({"state":"FAILED"}) or stopped without reaching a valid terminal state. Invalid terminal states could also be accepted instead of being returned to the model for correction.

This change makes terminal-state handling explicit across the per-file agent loop and its callers:

• DONE completes the task.
• FAILED terminates the task as a failure.
• Empty, unknown, non-string, or malformed states return a tool error so the model can retry.
• A loop that exits without successful task_done is propagated as a review or scan failure.
• Partial scan output and the session viewer use the same terminal-state semantics.
• Legacy task_done({}) remains a successful completion for compatibility.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change
• Refactoring
• Documentation update
• CI / Build / Tooling

How Has This Been Tested?

• Added executable regression coverage for explicit DONE, FAILED, invalid state retry, and missing completion.
• Added caller coverage for review and scan failure propagation.
• Added viewer coverage for terminal states and tool-result matching.
• Targeted regression tests pass.
• go vet passes for all affected packages.

Checklist

• My code follows the project coding style.
• I have performed a self-review.
• I have added tests that prove the fix is effective.
• Relevant tests pass locally.
• No user-facing documentation changes are required.
• I have signed the CLA.

Related Issues

No linked issue.

[CLAassistant]

All committers have signed the CLA.

[4-1-1]

CLA Assistant confirms that I signed the CLA as 4-1-1. I rechecked the original PR #578 and recreated it as this PR (#582), but the license/cla check remains pending. The status context currently shown on #582 still points to pullRequest=578 for commit 80f51414162dc5d3ff681aba20e69d606f5973c0, so it appears to be stale. Could a maintainer please retrigger or reset the CLA status for this commit/PR? Thank you.

[github-actions]

🔍 OpenCodeReview found 2 issue(s) in this PR.

• ✅ Successfully posted inline: 2 comment(s)

[4-1-1]

Hi @lizhengfeng101, the CLA is now green and this PR is mergeable. When convenient, could you please take a look?

It fixes per-file tasks incorrectly treating FAILED or incomplete terminal states as successful, while preserving compatibility with legacy task_done({}). Targeted regression tests and go vet for the affected packages pass.

Thank you!

[lizhengfeng101]

LGTM