add total build time to -v output, harden dispatchNamedObject

[cs01]

Summary

• chad build -v foo.ts now appends ` in Xms` to the existing `Compiled: ...` line. Cheap way to see total build time without reaching for the shell's `time`. No change at default verbosity.
• One-line workaround in `MethodCallGenerator.dispatchNamedObject` to harden it against a pre-existing native-compiler false positive in `checkMissingReturns`. Needed because any edit to `compileNative`'s body shifts AST layout enough to trip the false positive on that function — same class of bug we've hit before on `transformExpression`. The extra trailing `return null;` after the switch-with-default short-circuits `mrAllReturn` on the first reverse-iteration step and makes the function immune to future layout shifts.

Why the two changes ship together

They're not logically coupled, but they're operationally coupled: landing the timing change alone reliably trips the `dispatchNamedObject` false positive. Verified by bisection — even a 2-line timing edit is enough.

Test plan

• `npm run verify:quick` passes locally (tsc + Stage 0 build + Stage 1 self-build + Stage 1 smoke + unit tests)
• `chad build foo.ts` — no behavior change
• `chad build foo.ts -v` — `Compiled: foo in 26621ms` appears
• CI green

Root cause note

The underlying `checkMissingReturns` / `mrAllReturn` codegen bug is documented in memory (`native-missing-returns-false-positive.md`) for future sessions. This PR is a workaround for that specific function, not a fix for the root cause. The real fix lives in `src/semantic/safety-checks.ts` `mrAllReturn` and is a separate effort.

[github-actions]

Benchmark Results (Linux x86-64)

Benchmark	C	ChadScript	Go	Node	Bun	Place
Binary Trees	1.379s	1.251s	2.700s	1.177s	0.967s	🥉
Cold Start	1.0ms	0.8ms	1.2ms	27.0ms	9.1ms	🥇
Fibonacci	0.814s	1.472s	1.562s	3.180s	1.976s	🥈
File I/O	0.116s	0.092s	0.088s	0.199s	0.175s	🥈
JSON Parse/Stringify	0.004s	0.005s	0.017s	0.015s	0.007s	🥈
Matrix Multiply	0.446s	0.696s	0.613s	0.374s	0.327s	#5
Monte Carlo Pi	0.389s	0.410s	0.404s	2.248s	6.049s	🥉
N-Body Simulation	1.665s	2.121s	2.201s	2.395s	3.249s	🥈
Quicksort	0.214s	0.244s	0.213s	0.262s	0.226s	#4
SQLite	0.348s	0.404s	—	0.415s	0.399s	🥉
Sieve of Eratosthenes	0.016s	0.028s	0.020s	0.040s	0.036s	🥉
String Manipulation	0.008s	0.046s	0.016s	0.036s	0.028s	#5

CLI Tool Benchmarks

Benchmark	ChadScript	grep	node	xxd	Place
Hex Dump	0.427s	—	0.994s	0.130s	🥈
Recursive Grep	0.019s	0.010s	0.097s	—	🥈