fix: match Lua unary minus, for-in multi-return, and native range checks

[esrrhs]

Summary

• Lexer keeps unary minus out of number tokens so 1-2, -1 table keys, and math.abs(mininteger) match Lua 5.4; expression values still treat 1.0/0.0 as floats.
• Generic for-in preserves 1/2/3-value iterator factories, colon methods evaluate the prefix before args, and VmFunction::Merge takes the latest arity.
• HTTP/WS, INI, YAML, Redis, MySQL pool, and net helpers reject out-of-range or unsafe input instead of wrapping or injecting.

Test plan

• Targeted regressions: jitter.nan_float_for, test_math.test_math_boundary_integer, unary-minus/for-in/method-order/native bound tests
• GitHub Actions CI on this PR (full unit_tests still re-running locally)

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Codecov Report

❌ Patch coverage is 79.66102% with 60 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.80%. Comparing base (d1ba6a5) to head (31a4ab0).

Files with missing lines	Patch %	Lines
src/native/yaml/native_yaml.cpp	45.45%	18 Missing ⚠️
src/native/redis/native_redis.cpp	65.78%	13 Missing ⚠️
src/interp/codegen.cpp	73.33%	12 Missing ⚠️
src/native/net/net_event.cpp	74.07%	7 Missing ⚠️
src/compile/compile_common.h	88.37%	5 Missing ⚠️
src/compile/c_gen.cpp	94.54%	3 Missing ⚠️
src/native/http/native_http.cpp	83.33%	1 Missing ⚠️
src/native/mysql/native_mysql_pool.cpp	0.00%	1 Missing ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##           master      #18      +/-   ##
==========================================
- Coverage   87.89%   87.80%   -0.10%     
==========================================
  Files         119      119              
  Lines       23842    24042     +200     
==========================================
+ Hits        20955    21109     +154     
- Misses       2887     2933      +46     

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