Bump Spring Boot 4 to RC1

[adinauer]

📜 Description

Bump Spring Boot 4 to RC1

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

• I added GH Issue ID & Linear ID
• 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.

🔮 Next steps

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	356.88 ms	419.56 ms	62.69 ms
Size	1.58 MiB	2.12 MiB	549.42 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
d364ace	382.77 ms	443.21 ms	60.44 ms
3998a95	415.94 ms	478.54 ms	62.60 ms
806307f	357.85 ms	424.64 ms	66.79 ms
ee747ae	357.79 ms	421.84 ms	64.05 ms
d217708	355.34 ms	381.39 ms	26.05 ms
ee747ae	396.82 ms	441.67 ms	44.86 ms
604a261	380.65 ms	451.27 ms	70.62 ms
3699cd5	423.60 ms	495.52 ms	71.92 ms
b3d8889	371.84 ms	447.49 ms	75.65 ms
d5a29b6	298.62 ms	391.78 ms	93.16 ms

App size

Revision	Plain	With Sentry	Diff
d364ace	1.58 MiB	2.11 MiB	539.75 KiB
3998a95	1.58 MiB	2.10 MiB	532.96 KiB
806307f	1.58 MiB	2.10 MiB	533.42 KiB
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
d217708	1.58 MiB	2.10 MiB	532.97 KiB
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
604a261	1.58 MiB	2.10 MiB	533.42 KiB
3699cd5	1.58 MiB	2.10 MiB	533.45 KiB
b3d8889	1.58 MiB	2.10 MiB	535.07 KiB
d5a29b6	1.58 MiB	2.12 MiB	549.37 KiB

Previous results on branch: feat/bump-spring-boot-4-rc1

Startup times

Revision	Plain	With Sentry	Diff
97185ec	308.43 ms	363.24 ms	54.81 ms

App size

Revision	Plain	With Sentry	Diff
97185ec	1.58 MiB	2.12 MiB	549.42 KiB

[cursor]

Bug: Test Timing Issue Causes Inconsistent Results

Race condition in test logic: The original test used await.during(Duration.ofSeconds(2)).untilAsserted to wait and verify that no events were sent for handled exceptions. The change to immediate verification with verify(transport, never()) creates a race condition where the test could incorrectly pass if Sentry events are sent asynchronously after the verification. This is particularly problematic since other tests in the same file still use await.untilAsserted, indicating that asynchronous processing occurs in this system.