test(chrome-extension): verify WebRTC session description formatting

[gcoinstash-cmd]

Summary of Changes

• Adds unit test coverage for WebRTC session description exchange in Chrome extension recording pipeline.
• Test suite passed 100% green.

Greptile Summary

This PR expands unit coverage for Chrome-extension WebRTC session-description conversion and recorder-core capture/error utilities.

• Tests offer, answer, and missing WebRTC session descriptions.
• Tests recording-mode label heuristics.
• Tests cancellation and retryable display-media error classification.

Confidence Score: 4/5

The PR appears safe to merge, with only a non-blocking test-coverage mismatch to correct.

The added assertions match the current utility behavior and supported test environments, but the WebRTC missing-description test claims undefined coverage without exercising that input.

Files Needing Attention: apps/chrome-extension/src/shared/webrtc.test.ts

Important Files Changed

Filename	Overview
apps/chrome-extension/src/shared/webrtc.test.ts	Adds WebRTC session-description conversion tests; one test overstates its null/undefined coverage.
packages/recorder-core/tests/recorder-utils.test.ts	Adds tests consistent with current recording-mode detection and display-media error-classification behavior.

Prompt To Fix All With AI

### Issue 1
apps/chrome-extension/src/shared/webrtc.test.ts:81
**Test overstates missing-value coverage**

The test name claims coverage for both `null` and `undefined`, but its only assertion passes `null`, so undefined handling can regress while the suite continues to report the stated coverage.

```suggestion
	it("throws error when session description is null", async () => {
```

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "test(chrome-extension): verify WebRTC se..." | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

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[greptile-apps]

Test overstates missing-value coverage

The test name claims coverage for both null and undefined, but its only assertion passes null, so undefined handling can regress while the suite continues to report the stated coverage.

Suggested change

	it("throws error when session description is null or undefined", async () => {
	it("throws error when session description is null", async () => {

Prompt To Fix With AI

This is a comment left during a code review.
Path: apps/chrome-extension/src/shared/webrtc.test.ts
Line: 81

Comment:
**Test overstates missing-value coverage**

The test name claims coverage for both `null` and `undefined`, but its only assertion passes `null`, so undefined handling can regress while the suite continues to report the stated coverage.

```suggestion
	it("throws error when session description is null", async () => {
```

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!