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

Adds unit coverage for Chrome-extension WebRTC session-description conversion and shared recorder utility behavior.

• Verifies offer and answer conversion plus missing-description rejection.
• Covers recording-mode label heuristics, cancellation classification, and display-media retry classification.

Confidence Score: 4/5

The PR appears safe to merge, with only a non-blocking mismatch between one test name and the input it exercises.

The added tests do not alter production behavior and match the current utility contracts; the only accepted concern is misleading undefined-coverage wording in the WebRTC test.

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 focused session-description conversion tests, with one test title overstating its exercised inputs.
packages/recorder-core/tests/recorder-utils.test.ts	Adds tests matching current recording-mode detection and display-capture error classification behavior.

Prompt To Fix All With AI

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

The test advertises both null and undefined coverage but invokes `toSessionDescriptionInit` only with null, obscuring the fact that undefined is not independently exercised.

```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 name overstates coverage

The test advertises both null and undefined coverage but invokes toSessionDescriptionInit only with null, obscuring the fact that undefined is not independently exercised.

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 name overstates coverage**

The test advertises both null and undefined coverage but invokes `toSessionDescriptionInit` only with null, obscuring the fact that undefined is not independently exercised.

```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!