Fix APK handler spinning on closed temp file after context timeout

[dipto-truffle]

Summary

• The APK handler's processAPK loop in pkg/handlers/apk.go did not check for context cancellation, causing it to iterate through every file in a zip archive even after the 60s maxTimeout fires and the underlying temp file is closed. This produced ~2000 "file already closed" error log entries per APK and wasted scanner CPU/IO, contributing to slow scans for co-located jobs.
• Added a common.IsDone(ctx) check at the top of the file iteration loop, matching the established pattern already used by archive.go, ar.go, and rpm.go in the same package.
• Added unit tests verifying that processAPK exits promptly on both context cancellation and deadline exceeded.

Vendors trufflesecurity/thog#6007

Test plan

• go test ./pkg/handlers/ -run TestProcessAPK_ExitsOn -v passes (context cancellation + deadline exceeded)
• Deploy to a dev environment and verify that APK processing no longer produces thousands of "file already closed" log entries after timeout
• Confirm scan throughput is not degraded

Made with Cursor

---

Note

Low Risk
Low risk: adds an early-exit context check in the APK file iteration loop and corresponding unit tests, with minimal impact on normal processing aside from stopping work sooner on cancellation/timeouts.

Overview
Ensures APK scanning stops promptly when the processing context is cancelled or times out by adding a common.IsDone(ctx) guard in apkHandler.processAPK before iterating each zip entry.

Adds unit tests that build a minimal in-memory APK and assert processAPK returns context.Canceled and context.DeadlineExceeded rather than continuing to process files after cancellation.

^{Reviewed by Cursor Bugbot for commit f7c44b4. Bugbot is set up for automated code reviews on this repo. Configure here.}