feat(compose): app.onError handles a non-Error object

[yusukebe]

Resolves #667

The original code is #667 (comment) by @usualoma

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 (e3bf8c8)	#4438 (9a5e23c)	+/-
Bundle Size (B)	18,294B	18,351B	57B
Bundle Size (KB)	17.87K	17.92K	0.05K

Compiler Diagnostics (tsc)

	main (e3bf8c8)	#4438 (9a5e23c)	+/-
Files	300	300	0
Lines	140,207	140,211	4
Identifiers	127,056	127,064	8
Symbols	264,249	264,254	5
Types	155,889	155,892	3
Instantiations	538,872	538,872	0
Memory used	309,149K	324,418K	15,269K
I/O read	0.03s	0.03s	0s
I/O write	0s	0s	0s
Parse time	0.84s	0.84s	0s
Bind time	0.38s	0.34s	-0.04s
Check time	3.01s	3.02s	0.01s
Emit time	0s	0s	0s
Total time	4.24s	4.21s	-0.03s

Compiler Diagnostics (typescript-go)

	main (e3bf8c8)	#4438 (9a5e23c)	+/-
Files	269	269	0
Lines	118,096	118,100	4
Identifiers	116,489	116,497	8
Symbols	353,956	353,961	5
Types	277,831	277,835	4
Instantiations	3,528,587	3,528,587	0
Memory used	223,118K	223,148K	30K
Memory allocs	10,491,772	10,491,773	1
Parse time	0.087s	0.073s	-0.014s
Bind time	0.021s	0.019s	-0.002s
Check time	1.484s	1.446s	-0.038s
Emit time	0s	0s	0s
Total time	1.604s	1.55s	-0.054s

---

Reported by octocov

[github-actions]

HTTP Performance Benchmark

Framework	Runtime	Average	Ping	Query	Body
hono (origin/main)	bun	38,242.94	52,189.25	33,564.78	28,974.79
hono (current)	bun	38,350.38	52,519.10	33,947.97	28,584.08
Change		+0.28%	+0.63%	+1.14%	-1.35%

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.26%. Comparing base (e3bf8c8) to head (56d0d47).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4438   +/-   ##
=======================================
  Coverage   91.25%   91.26%           
=======================================
  Files         171      171           
  Lines       10915    10919    +4     
  Branches     3146     3149    +3     
=======================================
+ Hits         9961     9965    +4     
  Misses        953      953           
  Partials        1        1           

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