fix: cancel pending KSCrash report processing

[supervacuus]

#skip-changelog (for V10)

📜 Description

Fixes #8535 on top of #8515.

This adds a generation-scoped report-processing session that is canceled upon SentryKSCrash.Integration uninstallation.

Queued or pre-capture work completes with a retryable error, while work that has committed to client capture finishes normally. Canceled drains also stop before processing another report or running end-of-drain cleanup.

Rergarding review and merge process:

• I will let this mark as non-draft so that the bots can have a go, but will move it back to draft, because this is built on top of feat: process pending KSCrash reports #8515, which has not yet been reviewed, and so this should not be reviewed before that.
• I deliberately do not want to stack on top of the current stack with KSCrash: install crash handler  #8469 and feat: process pending KSCrash reports #8515, because ideally we can merge those to main before reviewing here starts. However, if people consider correct lifecycle handling of pending report processing a precondition for merging feat: process pending KSCrash reports #8515, we can stack it on top.

💡 Motivation and Context

Pending KSCrash report processing currently outlives its integration. After SentrySDK.close(), stale work can continue without a client or be captured upon a later SDK start.

The processing session provides nonblocking cancellation, exactly-once filter completion, and isolation between SDK generations.

💚 How did you test it?

Added deterministic tests covering:

• queued and in-progress cancellation
• cancellation racing completion
• the capture commit boundary
• hub replacement and SDK restart isolation
• sender iteration and cleanup cancellation
• distinct sessions across integration restarts

Also ran the KSCrash-enabled iOS and macOS test suites locally.

I will follow up with a real on-disk retry and cleanup across launches testing in #8593 (tracking issue: #8539).

📝 Checklist

You have to check all boxes before merging:

• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.
• Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec.
• If I added a new public API, I also added it to the SentryObjC wrapper.

[sentry]

📲 Install Builds

iOS

🔗 App Name	App ID	Version	Configuration
SDK-Size	io.sentry.sample.SDK-Size	9.23.0 (1)	Release

⚙️ sentry-cocoa Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1212.83 ms	1251.37 ms	38.54 ms
Size	24.14 KiB	1.24 MiB	1.22 MiB

Baseline results on branch: supervacuus/feat/kscrash-report-sink

Startup times

Revision	Plain	With Sentry	Diff
8576fa5	1215.66 ms	1256.45 ms	40.79 ms
ea690ac	1217.16 ms	1261.51 ms	44.35 ms
ffce4be	1241.52 ms	1269.87 ms	28.35 ms
941ad74	1214.30 ms	1247.06 ms	32.76 ms
053e1df	1242.04 ms	1276.19 ms	34.15 ms
edd3780	1226.46 ms	1260.02 ms	33.57 ms
700456f	1225.04 ms	1259.40 ms	34.36 ms
68e2865	1213.20 ms	1251.37 ms	38.16 ms
718b8fd	1221.45 ms	1241.13 ms	19.68 ms

App size

Revision	Plain	With Sentry	Diff
8576fa5	24.14 KiB	1.24 MiB	1.22 MiB
ea690ac	24.14 KiB	1.24 MiB	1.22 MiB
ffce4be	24.14 KiB	1.24 MiB	1.22 MiB
941ad74	24.14 KiB	1.25 MiB	1.22 MiB
053e1df	24.14 KiB	1.24 MiB	1.22 MiB
edd3780	24.14 KiB	1.24 MiB	1.22 MiB
700456f	24.14 KiB	1.24 MiB	1.21 MiB
68e2865	24.14 KiB	1.24 MiB	1.22 MiB
718b8fd	24.14 KiB	1.24 MiB	1.22 MiB