A locally read-only identifier is not necessarily stable across a side-effecting call. ESM imports are live bindings, Script-root bindings can be changed by another script, and computed assignment keys bypassed the existing closed-over-TDZ guard. Single-use substitution could therefore move a binding read before a call and change program behavior.

The same incomplete stability query affected logical-assignment folding. A live imported member base could be cached before a call that reassigns the export, making `||=` or `??=` update the old object instead of the current binding.

Build on the shared reorder predicates from #24699. Imports, Script-root bindings, unresolved references, syntactically mutated symbols, and closed-over block-scoped reads are treated conservatively across ordinary reads, assignment-target objects, computed keys, and member-base folding. Stable module bindings and pure replacements remain optimizable.

## Example

```js
var key = "x";
function init(obj) {
  let value = mutate();
  obj[key] = value;
}
```

The previous substitution could produce:

```js
var key = "x";
function init(obj) {
  obj[key] = mutate();
}
```

That captures `key` before `mutate()` runs, although another script can change the global binding during the call. The declaration is now retained so the read remains after `mutate()`.

For imported member bases, main can rewrite `x.y || (mutate(), x.y = 3)` to `x.y ||= (mutate(), 3)`. When `mutate` reassigns the exported `x`, the original two-module runtime repro produces `3`, while the rewritten program produces `0`. The shared stability guard now prevents that fold.

Plain computed assignments still inline stable identifiers and literals. ECMAScript evaluates the key expression and `GetValue` before the right-hand side, but defers `ToPropertyKey` until the final `PutValue`, so arbitrary key expressions remain conservative without losing safe simple-key substitutions.

This improves the existing reorder guard; it does not add a general TDZ model. Sloppy mapped `arguments` mutation remains a pre-existing unsupported case and is outside this stack.

Verified with the full `oxc_minifier` suite (622 passed, 42 ignored), clippy with warnings denied, formatting, minsize, allocation snapshots, runtime ordering probes, and repeat-compression checks. `cargo minsize` measured 18 additional raw bytes across `echarts.js` and `typescript.js`, with no iteration-count changes. System-allocation metrics are unchanged; arena changes are dominated by retained code with minor fold-path shifts.

## Stack

1. #24699 — centralize reorder stability checks
2. **#24698 — guard reordered identifier reads**

AI assistance: Codex and Claude were used for implementation, adversarial review, and verification. The contributor remains responsible for reviewing, understanding, and submitting the changes under the repository AI usage policy.