Refactor array submodules

[cs01]

Refactor array codegen into submodules

Break down the monolithic array.ts (3500+ lines) into focused submodule files under array/, matching the pattern already used by string/ submodules.

What changed

• array.ts — reduced from ~3500 lines to a thin facade (~210 lines) that delegates to submodules
• array/search-predicate.ts (new) — find, some, every, includes with their string-array variants
• array/iteration.ts (new) — filter, forEach, reduce, map with their string-array variants
• array/combine.ts (new) — join, slice, concat, spread literals with their string-array variants
• array/context.ts — added shared loadArrayMeta and detectArrayType helpers, unified on IGeneratorContext
• array/literal.ts, array/mutators.ts — minor cleanup to use unified IGeneratorContext

Design

• All submodule functions take IGeneratorContext directly (same pattern as string submodules)
• findIndex and sort keep predicate/comparator resolution in the facade since they need pre-resolved values before delegating
• Shared helpers (loadArrayMeta, detectArrayType) live in context.ts to avoid name collisions across submodule files
• .claude/rules.md updated to document the new submodule structure

Test plan

• All 29 array test fixtures pass with native compiler
• Full 3-stage self-hosting passes (Stage 0 → Stage 1 → Stage 2)
• TypeScript compiles cleanly