fix(codegen): annotator only caches truly-static expression types; unblocks typeOf consumer migrations

[cs01]

Root-cause fix. The AST type annotator (src/semantic/type-annotator.ts) was populating the typeOf cache for every expression pre-codegen. But arrays/binary/conditional/new/object/map/set/type_assertion expressions recurse into the symbol table (isString, getType) whose answers only exist mid-codegen. Cached pre-codegen → stale wrong answer; downstream consumers reading base/arrayDepth from that cached rich object got misclassified types → native IR type mismatches.

Diagnostic trail: the previous attempt to migrate variable-allocator (PR #578 rollback) failed with '%N' defined with type 'double' but expected 'ptr' on stage 1 self-compile. Side-effect test showed calling typeOf+discarding worked; using its return broke — proved the returned value was wrong, not a side effect. Instrumentation side-by-side (typeOf vs flat) found 397 divergences: 342 array (number[] vs string[]), 29 conditional, 26 binary. All caused by annotator caching with empty symbol table.

Fix: shrink annotator's cache-set to truly-static types (number/string/template_literal/boolean/null/regex). Everything else resolves live via typeOf's fallback to resolveExpressionTypeRich.

Also in this PR: variable-allocator.ts uses typeOf() at the decl-type site — was rolled back in #578 due to this bug; now safe with the annotator fix. Pattern for future consumer migrations is now sound.

Test plan:

• Stage 0 native compile of src/chad-native.ts — clean
• Full npm run verify (stage 0/1/2 + tests) — Verification PASSED
• CI green

🤖 Generated with Claude Code

[github-actions]

Benchmark Results (Linux x86-64)

Benchmark	C	ChadScript	Go	Node	Place
Cold Start	1.1ms	0.9ms	1.3ms	28.0ms	🥇
Fibonacci	0.814s	0.765s	1.559s	3.160s	🥇
Hash Map Lookup	0.090s	0.063s	0.091s	0.112s	🥇
Binary Trees	1.456s	1.294s	2.755s	1.181s	🥈
File I/O	0.119s	0.093s	0.086s	0.207s	🥈
JSON Parse/Stringify	0.035s	0.052s	0.175s	0.136s	🥈
N-Body Simulation	1.666s	2.119s	2.202s	2.390s	🥈
Regex Match	0.016s	0.005s	0.021s	0.004s	🥈
SQLite	0.051s	0.365s	0.490s	0.419s	🥈
Monte Carlo Pi	0.389s	0.410s	0.405s	2.248s	🥉
Quicksort	0.215s	0.247s	0.213s	0.262s	🥉
Sieve of Eratosthenes	0.015s	0.026s	0.020s	0.040s	🥉
String Manipulation	0.008s	0.019s	0.016s	0.036s	🥉
Matrix Multiply	0.445s	0.740s	0.564s	0.381s	#4

CLI Tool Benchmarks

Benchmark	ChadScript	grep	node	xxd	Place
Hex Dump	0.558s	—	1.059s	0.131s	🥈
Recursive Grep	0.020s	0.010s	0.103s	—	🥈