feat(check): opt-in --layout proseCoverageFloor (#2834)

* feat(check): opt-in --layout proseCoverageFloor for text_occluded

Keep the default prose coverage floor at 0.15 for all callers, and allow
stricter agents (e.g. Zephyr) to lower it via --layout "proseCoverageFloor=0.05"
without changing other layout gates.

Co-authored-by: Cursor <cursoragent@cursor.com>

* style(check): collapse --layout comments and docs to one line

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(check): strict proseCoverageFloor parse + pin 0.07 floor tests

Reject trailing-garbage fractions that Number.parseFloat would accept, and
pin the existing ~0.07 coverage fixture for default vs floor=0.05 (atomic
labels unchanged) plus a collectLayout forwarding assertion.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(check): share parseNumberStrict across layout and frame-check

Sweep the sibling --frame-check tol parser (and caption fractions) onto the
same strict Number() helper so trailing garbage cannot prefix-parse.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/cli/src/commands/check.ts

@@ -16,7 +16,7 @@ import {
   type CheckReport,
   type CheckSection,
 } from "../utils/checkPipeline.js";
-import type { CaptionZoneOptions, FrameCheckOptions } from "../utils/checkTypes.js";
+import type { CaptionZoneOptions, FrameCheckOptions, LayoutOptions } from "../utils/checkTypes.js";
 
 export const examples: Example[] = [
   ["Run the full verification gate", "hyperframes check"],
@@ -120,6 +120,10 @@ export function createCheckCommand(
         description:
           'Bare --frame-check uses defaults (tol=2px, severity=warning, seek=.5; breach floor=max(120px, 6% of shorter canvas edge)); or pass "severity=error;seek=.25,.75;tol=4" to tune',
       },
+      layout: {
+        type: "string",
+        description: 'Layout knobs: "proseCoverageFloor=0.05" (0–1; default 0.15).',
+      },
     },
     async run({ args }) {
       const asJson = args.json === true;
@@ -168,6 +172,7 @@ function parseCheckOptions(args: Record<string, unknown>): CheckOptions {
     snapshots: args.snapshots === true,
     captionZone: parseCaptionZone(args["caption-zone"]),
     frameCheck: parseFrameCheck(args["frame-check"]),
+    layout: parseLayout(args.layout),
     autoProxy: args.proxy as boolean | undefined,
   };
 }
@@ -176,6 +181,8 @@ const CAPTION_ZONE_FIELDS = new Set(["x0", "y0", "x1", "y1", "severity", "seek"]
 
 const FRAME_CHECK_FIELDS = new Set(["severity", "seek", "tol"]);
 
+const LAYOUT_FIELDS = new Set(["proseCoverageFloor"]);
+
 // Mirrors --caption-zone's spec grammar so the EF bridge's severity/seek/tol
 // options survive the migration instead of being silently dropped by a
 // boolean flag (bare --frame-check keeps today's defaults).
@@ -206,8 +213,8 @@ function parseFrameCheckFields(value: string): Map<string, string> {
 
 function parseFrameCheckTolerance(raw: string | undefined): number | undefined {
   if (raw === undefined) return undefined;
-  const tol = Number.parseFloat(raw);
-  if (!Number.isFinite(tol) || tol < 0) throw frameCheckError();
+  const tol = parseNumberStrict(raw);
+  if (tol === null || tol < 0) throw frameCheckError();
   return tol;
 }
 
@@ -217,6 +224,52 @@ function frameCheckError(): Error {
   );
 }
 
+/** Parse `--layout "proseCoverageFloor=0.05"` (semicolon-separated key=value, like caption-zone). */
+export function parseLayout(value: unknown): LayoutOptions | undefined {
+  if (value === undefined || value === null || value === false) return undefined;
+  if (value === true || value === "") throw layoutError();
+  if (typeof value !== "string") throw layoutError();
+  const fields = parseLayoutFields(value);
+  const proseCoverageFloor = parseProseCoverageFloor(fields.get("proseCoverageFloor"));
+  if (proseCoverageFloor === undefined) throw layoutError();
+  return { proseCoverageFloor };
+}
+
+function parseLayoutFields(value: string): Map<string, string> {
+  const fields = new Map<string, string>();
+  for (const part of value.split(";")) {
+    const trimmed = part.trim();
+    if (!trimmed) continue;
+    const separator = trimmed.indexOf("=");
+    if (separator <= 0) throw layoutError();
+    const key = trimmed.slice(0, separator).trim();
+    const entry = trimmed.slice(separator + 1).trim();
+    if (!LAYOUT_FIELDS.has(key) || fields.has(key)) throw layoutError();
+    fields.set(key, entry);
+  }
+  return fields;
+}
+
+function parseProseCoverageFloor(raw: string | undefined): number | undefined {
+  if (raw === undefined) return undefined;
+  const floor = parseNumberStrict(raw);
+  if (floor === null || floor < 0 || floor > 1) throw layoutError();
+  return floor;
+}
+
+function layoutError(): Error {
+  return new Error(
+    'Invalid --layout: use "proseCoverageFloor=0.05" with a fraction from 0 to 1 (inclusive)',
+  );
+}
+
+/** Reject trailing garbage that Number.parseFloat would silently accept (`4px`, `0.05abc`). */
+function parseNumberStrict(raw: string): number | null {
+  if (raw === "") return null;
+  const value = Number(raw);
+  return Number.isFinite(value) ? value : null;
+}
+
 function parseCaptionZone(value: unknown): CaptionZoneOptions | undefined {
   if (value === undefined || value === null) return undefined;
   const fields = parseCaptionFields(captionZoneString(value));
@@ -279,8 +332,8 @@ function requiredCaptionFraction(fields: Map<string, string>, key: string): numb
 
 function captionFraction(value: string | undefined): number | null {
   if (value === undefined || value === "") return null;
-  const parsed = Number(value);
-  return Number.isFinite(parsed) && parsed >= 0 && parsed <= 1 ? parsed : null;
+  const parsed = parseNumberStrict(value);
+  return parsed !== null && parsed >= 0 && parsed <= 1 ? parsed : null;
 }
 
 function captionSeverity(value: string | undefined): "error" | "warning" | undefined {