fix(jsx): handle useSyncExternalStore subscription and snapshot changes

[usualoma]

fixes #5162

The reported issue can be addressed by making the subscription effect depend on subscribe. This PR goes slightly further and also handles changes to getSnapshot:

• Re-subscribe when subscribe changes.
• Keep the previous subscription active until the new subscription is installed during the effect flush.
• Read the snapshot during render so a changed getSnapshot is reflected without waiting for a store notification.
• Re-check the latest snapshot after subscribing to avoid missing an update between render and effect execution.
• Add regression tests for changing subscribe and getSnapshot.

While investigating this, I also explored fixing the underlying deferred effect and cleanup behavior. Since that would affect all effect hooks and needs broader review, it is intentionally kept out of this PR; see the draft PoC in #5165.

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code

[github-actions]

Bundle size check

	main (26d8e42)	#5166 (2819497)	+/-
Bundle Size (B)	19,032B	19,032B	0B
Bundle Size (KB)	18.59K	18.59K	0K

Compiler Diagnostics (tsc)

	main (26d8e42)	#5166 (2819497)	+/-
Files	83	83	0
Lines	59,439	59,439	0
Identifiers	60,614	60,614	0
Symbols	105,939	105,939	0
Types	159,727	159,727	0
Instantiations	413,958	413,958	0
Memory used	167,608K	168,654K	1,046K
I/O read	0.01s	0.01s	0s
I/O write	0s	0s	0s
Parse time	0.35s	0.4s	0.05s
Bind time	0.16s	0.15s	-0.01s
Check time	1.4s	1.36s	-0.04s
Emit time	0s	0s	0s
Total time	1.91s	1.91s	0s

Compiler Diagnostics (typescript-go)

	main (26d8e42)	#5166 (2819497)	+/-
Files	215	215	0
Lines	147,087	147,087	0
Identifiers	121,968	121,968	0
Symbols	188,307	188,307	0
Types	259,012	259,012	0
Instantiations	621,523	621,523	0
Memory used	160,754K	160,817K	63K
Memory allocs	1,776,854	1,776,623	-231
Config time	0.001s	0.001s	0s
BuildInfo read time	0s	0s	0s
Parse time	0.097s	0.09s	-0.007s
Bind time	0s	0s	0s
Check time	0.455s	0.456s	0.001s
Emit time	0.005s	0.005s	0s
Changes compute time	0.024s	0.024s	0s
Total time	0.621s	0.614s	-0.007s

---

Reported by octocov

[usualoma]

Hi @yusukebe,
Could you please leave a review?

[github-actions]

HTTP Performance Benchmark

Framework	Runtime	Average	Ping	Query	Body
hono (origin/main)	bun	62,879.75	81,314.61	59,363.85	47,960.78
hono (current)	bun	63,106.27	81,433.31	59,952.22	47,933.28
Change		+0.36%	+0.15%	+0.99%	-0.06%

[codecov]

Codecov Report

❌ Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.09%. Comparing base (c285f9a) to head (0c7ad71).
⚠️ Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
src/jsx/hooks/index.ts	86.66%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5166   +/-   ##
=======================================
  Coverage   79.08%   79.09%           
=======================================
  Files         154      154           
  Lines       10764    10782   +18     
  Branches     2254     2253    -1     
=======================================
+ Hits         8513     8528   +15     
- Misses       2251     2254    +3     

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[yusukebe]

LGTM!

[yusukebe]

@usualoma

Thank you!