[codex] Fix native instance walk for fluent chains

[andrewtdiz]

Summary

Fixes the local native-instance rewrite pass so non-native fluent call chains are walked linearly instead of revisiting the same property receiver at every chain level.

The OpenCode/Perry graph previously reached module collection/tree-shake and then timed out in run_native_instance_fixups while processing the long yargs chain in the OpenCode overlay src/index.ts. The Cheerio chained-call special case recursively fixed a property receiver, then the generic fallback walked the whole callee again, making long non-native fluent chains exponential.

Changes

• Tracks when the property receiver has already been recursively fixed in fix_native_instance_expr_with_locals.
• Skips the duplicate generic callee recursion in that case while still visiting call arguments.
• Adds a regression that constructs a non-native fluent HIR chain directly and runs fix_local_native_instances over it.

Validation

• cargo test -p perry-hir --test cheerio_call_rewrite -> 2 passed; 0 failed.
• cargo build --release -p perry -> finished release build.
• Direct OpenCode compile repro with the fixed release binary moved past the previous native-fixup timeout, reached Found 2760 module(s): 2760 native, 0 JavaScript, entered Generating code..., then hit the next compiler blocker: thread '<unknown>' has overflowed its stack during codegen.
• OpenTUI harness with the fixed release binary also moved past native-fixup and failed at the next codegen stack overflow. Kept temp dir: /var/folders/8q/vx4z9tqd08jd1b5_bykzbdkr0000gn/T/opentui-perry-native-Irv8KZ.

Notes

This does not complete the OpenTUI/OpenCode Perry-native migration. It only moves the fluent-chain/native-fixup timeout blocker; the next blocker is a Perry codegen stack overflow before a binary is produced.