Optional JSDoc rejects mandatory JavaScript setter parameters

The generated Symbolic bindings used by the full Sentry CLI document several JavaScript setter parameters as optional in JSDoc. The executable parameters themselves are mandatory. Node accepts these setters, but scriptc rejects them before lowering.

This follows up on #3036 and #3044. They were closed as fixed by #3112, but that merged diff contains the regex change; current main still rejects this example:

class Store {
  constructor() { this.stored = null; }
  /** @param {string | null} [next] */
  set value(next) { this.stored = next; }
}
const store = new Store();
store.value = "kept";
console.log(store.stored);

Node prints kept. scriptc reports SC0001: A 'set' accessor cannot have an optional parameter. The diagnostic points into the JSDoc comment, not an executable ? parameter. The same problem occurs for object-literal setters and with // @ts-check.

The parser represents the optional JSDoc annotation with a synthetic optional token, and the preflight gate treats it as executable setter syntax. The full CLI currently has five instances of this diagnostic in Symbolic's generated bindings.

The requested fix should admit this comment-only JavaScript case while preserving errors for real optional, default, rest, or multiple setter parameters and keeping caller type checks and reflective argument-count restrictions intact.

A dependency can contain many documented setters, so eligibility should not rescan the whole file for every diagnostic. A per-preflight index keyed by SourceFile identity can collect attached comment spans once and find a containing span with binary search. SourceFile identity matters because original and rewritten JSX snapshots can share a filename but have different offsets.

Regression coverage should include class and object setters, checked JavaScript, the real syntax negatives, many setters, and JSX snapshots sharing a filename. Native differential coverage should check assignments, stored values, descriptor behavior, and observable side effects against Node.

Reproduced with scriptc 0.4.9 built from current main and Node 24.22.1. The current-main positive setter tests fail with TS1051 before any production change. Related earlier work: #3036, #3044, #3112.