[WIP] feat: introduce Route Check Middleware

[yusukebe]

Resolve #4701

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[github-actions]

Bundle size check

	main (69ad885)	#4703 (15fa50c)	+/-
Bundle Size (B)	18,438B	18,438B	0B
Bundle Size (KB)	18.01K	18.01K	0K

Compiler Diagnostics (tsc)

	main (69ad885)	#4703 (15fa50c)	+/-
Files	303	303	0
Lines	141,175	141,175	0
Identifiers	128,951	128,951	0
Symbols	269,501	269,501	0
Types	202,701	202,701	0
Instantiations	609,801	609,801	0
Memory used	337,802K	345,468K	7,666K
I/O read	0.02s	0.02s	0s
I/O write	0s	0s	0s
Parse time	0.82s	0.71s	-0.11s
Bind time	0.34s	0.29s	-0.05s
Check time	2.7s	2.43s	-0.27s
Emit time	0s	0s	0s
Total time	3.86s	3.44s	-0.42s

Compiler Diagnostics (typescript-go)

	main (69ad885)	#4703 (15fa50c)	+/-
Files	303	303	0
Lines	141,177	141,177	0
Identifiers	128,914	128,914	0
Symbols	391,801	390,831	-970
Types	372,904	372,904	0
Instantiations	984,004	984,004	0
Memory used	254,559K	254,296K	-263K
Memory allocs	2,553,364	2,553,368	4
Config time	0.001s	0.001s	0s
Parse time	0.094s	0.089s	-0.005s
Bind time	0.018s	0.032s	0.014s
Check time	0.664s	0.662s	-0.002s
Emit time	0s	0s	0s
Total time	0.879s	0.836s	-0.043s

---

Reported by octocov

[github-actions]

HTTP Performance Benchmark

Framework	Runtime	Average	Ping	Query	Body
hono (origin/main)	bun	36,250.33	51,487.53	31,447.69	25,815.78
hono (current)	bun	36,828.68	52,801.24	31,930.02	25,754.77
Change		+1.60%	+2.55%	+1.53%	-0.24%

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.44%. Comparing base (69ad885) to head (8bae958).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4703      +/-   ##
==========================================
+ Coverage   91.43%   91.44%   +0.01%     
==========================================
  Files         173      174       +1     
  Lines       11382    11396      +14     
  Branches     3302     3307       +5     
==========================================
+ Hits        10407    10421      +14     
  Misses        974      974              
  Partials        1        1              

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[BelovedYaoo]

Hi @yusukebe, thanks for working on this!

I've opened #4714 as a follow-up optimization for this middleware. It introduces a WeakMap cache to store the result of the isMiddleware and findTargetHandler checks.

Since handler identities are immutable at runtime, this avoids redundant recursive lookups for every request, optimizing the performance from O(depth) to O(1) while remaining safe for dynamic routes.

Feel free to check it out :)