feat(hono-base): introduce onUnknownError

[yusukebe]

Fixes #667

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 (9987081)	#4411 (3e82879)	+/-
Bundle Size (B)	18,311B	18,574B	263B
Bundle Size (KB)	17.88K	18.14K	0.26K

Compiler Diagnostics (tsc)

	main (9987081)	#4411 (3e82879)	+/-
Files	300	300	0
Lines	140,207	140,234	27
Identifiers	127,057	127,106	49
Symbols	264,250	264,570	320
Types	155,889	155,908	19
Instantiations	538,872	538,931	59
Memory used	312,772K	330,424K	17,652K
I/O read	0.02s	0.02s	0s
I/O write	0s	0s	0s
Parse time	0.8s	0.71s	-0.09s
Bind time	0.31s	0.3s	-0.01s
Check time	2.67s	2.68s	0.01s
Emit time	0s	0s	0s
Total time	3.77s	3.7s	-0.07s

Compiler Diagnostics (typescript-go)

	main (9987081)	#4411 (3e82879)	+/-
Files	269	269	0
Lines	118,096	118,123	27
Identifiers	116,490	116,539	49
Symbols	353,957	355,012	1,055
Types	277,832	277,864	32
Instantiations	3,528,587	3,528,685	98
Memory used	223,159K	223,403K	244K
Memory allocs	10,491,890	10,492,545	655
Parse time	0.081s	0.152s	0.071s
Bind time	0.018s	0.066s	0.048s
Check time	1.465s	1.636s	0.171s
Emit time	0s	0s	0s
Total time	1.576s	1.865s	0.289s

---

Reported by octocov

[github-actions]

HTTP Performance Benchmark

Framework	Runtime	Average	Ping	Query	Body
hono (origin/main)	bun	37,432.85	50,987.94	33,266.36	28,044.26
hono (current)	bun	36,043.98	48,693.53	31,574.71	27,863.70
Change		-3.71%	-4.50%	-5.09%	-0.64%