refactor(devx): the three sequential-double-blank comment-mask callers take maskCommentsAndLiterals (#16336)

PR #16300 converted the eight callers the card named that spelled the
comments+literals projection as `comment[i] | literal[i]` -> `blank`. Three more
files spell the identical projection as a SEQUENTIAL double `blank` --
`blank(source, comment)` then `blank(masked, literal)` -- a shape the card's
grep could not match, measured in the Release (0 disagreements over 6,206
files vs the export, live control 6,176).

- `check-keyed-text-bounds.mjs`'s `project` keeps its pair-return shape
  `{ masked, struct }` as a wrapper over `maskComments` / `maskCommentsAndLiterals`
  called separately, following PR #16300's own precedent.
- `check-runner-env-posture.mjs`'s `findRunnerEnvReads` composes the two masks
  inline; both are now the module's own exports.
- `check-widget-option-census.mjs`'s exported `structureMask` is a straight
  substitution (no external importers).

`js-comment-mask.mjs` untouched: no new export, no semantics change.

Behaviour byte-identical, proven per gate by diffing plain and `--self-test`
output on origin/main before and after: 6 runs, 6 empty diffs, exit 0 on every
side. Ablation control (literal half dropped; identity mask) moves at least
one reading for every gate except `check-widget-option-census`'s plain run,
which is unmoved by both legs -- a pre-existing property of today's real
spec/parser corpus content, not introduced by this conversion (behaviour is
provably identical to the deleted code). Closed by a differential proof: the
deleted sequential-double-blank spelling vs the replacement over 6,192 files
(106,979,676 chars), 0 disagreements, live control (comments-only vs
comments+literals) disagreeing on 6,167 files.

Part of #15776.


Claude-Session: https://claude.ai/code/session_01Vbw3RPgdtqesx4azk9SbW8

Co-authored-by: Claude <noreply@anthropic.com>

Author: baozhoutao

scripts/check-keyed-text-bounds.mjs

@@ -171,7 +171,7 @@ import { dirname, join, relative, resolve, sep } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
 import { isEntrypoint } from './invoked-as.mjs';
-import { blank, scanSource } from './js-comment-mask.mjs';
+import { blank, maskComments, maskCommentsAndLiterals, scanSource } from './js-comment-mask.mjs';
 
 // ── The self-test's own battery roster and floor (#13489) ──────────────────
 //
@@ -398,11 +398,13 @@ function unhintedFiles(relPaths) {
  * READ from. `struct` additionally has literal CONTENT blanked, delimiters
  * kept: it is what brackets are COUNTED on, so a `{` inside a string cannot
  * move the parse.
+ *
+ * Both are `js-comment-mask.mjs`'s own exports (#15776) rather than a
+ * composition re-derived here.
  */
 function project(source) {
-  const { comment, literal } = scanSource(source);
-  const masked = blank(source, comment);
-  return { masked, struct: blank(masked, literal) };
+  const masked = maskComments(source);
+  return { masked, struct: maskCommentsAndLiterals(source) };
 }
 
 const OPEN_TO_CLOSE = { '(': ')', '{': '}', '[': ']' };

scripts/check-runner-env-posture.mjs

@@ -77,7 +77,7 @@ import { readFileSync, readdirSync, statSync, existsSync } from 'node:fs';
 import { join, relative, resolve, sep } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
-import { scanSource, blank } from './js-comment-mask.mjs';
+import { maskComments, maskCommentsAndLiterals } from './js-comment-mask.mjs';
 import { isEntrypoint } from './invoked-as.mjs';
 
 // ── The self-test's own battery roster and floor (#13489) ──────────────────
@@ -254,12 +254,13 @@ export const RUNNER_ENV_BRACKET_PATTERN =
  *
  * Offsets are preserved by both maskings, so a reported line number still
  * points at the real line.
+ *
+ * Both are `js-comment-mask.mjs`'s own exports (#15776) rather than a
+ * composition re-derived here.
  */
 export function findRunnerEnvReads(source) {
-  const flags = scanSource(source);
-
-  const commentMasked = blank(source, flags.comment);
-  const bothMasked = blank(commentMasked, flags.literal);
+  const commentMasked = maskComments(source);
+  const bothMasked = maskCommentsAndLiterals(source);
 
   const seen = new Set();
   const out = [];

scripts/check-widget-option-census.mjs

@@ -119,7 +119,7 @@ import { fileURLToPath } from 'node:url';
 import process from 'node:process';
 
 import { isEntrypoint } from './invoked-as.mjs';
-import { blank, scanSource } from './js-comment-mask.mjs';
+import { maskCommentsAndLiterals } from './js-comment-mask.mjs';
 
 const HERE = dirname(fileURLToPath(import.meta.url));
 const REPO_ROOT = resolve(HERE, '..');
@@ -179,10 +179,12 @@ const NON_DECLARED_MEMBERS = [
  *
  * Delimiters survive (the scanner flags literal content, not its quotes), so a
  * quoted object key and an array of string literals are both still locatable.
+ *
+ * `js-comment-mask.mjs`'s own `maskCommentsAndLiterals` (#15776), not a
+ * composition re-derived here.
  */
 export function structureMask(source) {
-  const flags = scanSource(source);
-  return blank(blank(source, flags.comment), flags.literal);
+  return maskCommentsAndLiterals(source);
 }
 
 /**