String arguments corrupted when passed to cross-module functions inside callback scopes

[proggeramlug]

Bug Description

String literals and string variables passed as arguments to imported functions (cross-module calls) are corrupted to empty strings when called from inside a button click handler or other callback scope. The same calls work correctly at module initialization (top-level scope).

Reproduction

import { saveState, getState } from './data/store';

// This WORKS — module level:
saveState('key1', 'hello');       // stores 'hello' ✓
console.log(getState('key1'));    // returns 'hello' ✓

const btn = Button('Test', () => {
  // This FAILS — inside callback:
  saveState('key2', 'world');     // stores '' (empty) ✗
  console.log(getState('key2'));  // returns '' ✗
});

Verified via SQLite:

SELECT * FROM app_state;
-- key1|hello        -- module level: correct
-- key2|             -- callback scope: empty!

Impact

Any cross-module function call with string arguments inside a callback/closure receives empty or corrupted values. This affects:

• saveState(key, value) — value is empty
• createConnection({ name, host, ... }) — some fields are empty
• encodeURIComponent(str) — produces "undefined"

Likely Cause

The NaN-boxed string pointer (f64) is being stored as an i64 (raw pointer) in the local variable due to is_string optimization. When passed as an argument to a cross-module function that expects f64, the i64→f64 bitcast produces a different value than the original NaN-boxed f64. Related to #10.

[proggeramlug]

Fixed in v0.4.37 (bf9779d). Same root cause as #10 — is_string locals passed to cross-module function calls were NaN-boxed with POINTER_TAG instead of STRING_TAG. The JS interop paths (js_call_function, js_native_call_method) also did raw bitcast instead of proper NaN-boxing. Both are now fixed.