fix(dashboard): explain silent Radar cells on hover and gate them (#12937)

Validado numa worktree combinada com a onda de dashboard/monitoring desta leva sobre `release/v3.8.51`: typecheck:core limpo, check-api-typecheck OK (289), check-file-size OK após rebaseline, 130/131 nos testes focados — a falha restante é asserção de tempo de parede sob carga, verde 6/6 isolada.

Sentinela que não se explica (`—`, `?`) faz o leitor inventar a razão. Explicar no hover é metade; o `check:radar-sentinels` é a outra — sem o gate, a explicação apodrece na primeira coluna nova.

scripts/check/check-radar-sentinels.mjs

@@ -0,0 +1,94 @@
+#!/usr/bin/env node
+/**
+ * OmniRoute — Radar silent-cell structural gate.
+ *
+ * Asserts three structural invariants over the Radar catalog table —
+ * every absent-data sentinel in that table must carry an explaining title.
+ * (Rationale lives in the PR description; this header is self-contained on
+ * purpose — no local doc paths here, they would leak into the upstream diff.
+ * Sized to 3 known sites — extend with a 4th check if a new silent cell lands.):
+ *   1. limits cell wraps {formatLimits(entry)} in <span title={t("limitsUnknownHelp")}> on the "—" branch
+ *   2. context cell wraps the "—" branch in <span title={t("contextUnknownHelp")}>
+ *   3. capabilityBadge's "?" span carries title={t("capabilityUnknownHelp")}
+ *
+ * Single purpose: structural invariant over one file. i18n coverage lives in
+ * scripts/i18n/check-ui-keys-coverage.mjs — a red run here means a sentinel
+ * without explanation, never a locale threshold.
+ *
+ * Usage: npm run check:radar-sentinels  (exit 1 on any broken invariant)
+ */
+
+import { readFileSync } from "node:fs";
+import path from "node:path";
+import process from "node:process";
+import { fileURLToPath } from "node:url";
+
+const SCRIPT_DIR = path.dirname(fileURLToPath(import.meta.url));
+const ROOT = path.resolve(SCRIPT_DIR, "..", "..");
+const TABLE = path.join(
+  ROOT,
+  "src",
+  "app",
+  "(dashboard)",
+  "dashboard",
+  "radar",
+  "RadarCatalogTable.tsx"
+);
+
+function fail(message) {
+  console.error(`[radar-sentinels] FAIL ${message}`);
+}
+
+function main() {
+  const raw = readFileSync(TABLE, "utf8");
+  const src = raw.replace(/\/\/.*|\/\*[\s\S]*?\*\//g, ""); // commented call sites must not count (no URLs in this file at pin)
+  const failures = [];
+
+  // Invariant 1 — limits cell: the "—" branch of formatLimits is wrapped with the help title.
+  // Sized to the implementation shape (const limits + conditional span). Window {0,500}:
+  // prettier rewraps must not false-red. If a 4th silent cell is added one day,
+  // extend here with a 4th check — this gate is deliberately sized to known sites,
+  // not generic (static-explicit beats magic-generic for a 1-file, 3-site gate).
+  if (
+    !/const limits = formatLimits\(entry\)[\s\S]{0,500}<span title=\{t\("limitsUnknownHelp"\)\}>\{limits\}<\/span>/.test(
+      src
+    )
+  ) {
+    failures.push(
+      'limits cell: expected const limits + "—" branch wrapped in <span title={t("limitsUnknownHelp")}>{limits}</span>'
+    );
+  }
+
+  // Invariant 2 — context cell: the "—" branch carries the context help title.
+  if (!/<span title=\{t\("contextUnknownHelp"\)\}>—<\/span>/.test(src)) {
+    failures.push('context cell: expected <span title={t("contextUnknownHelp")}>—</span>');
+  }
+
+  // Invariant 3 — capabilityBadge: the unknown-state span carries the capability help title.
+  // Post-fix shape (param form): helper takes `unknownHelp: string`,
+  // ALL THREE call sites (tools/vision/thinking) pass t("capabilityUnknownHelp") —
+  // count, not exist (one dropped site must go red), and the span spreads
+  // `{...(unknown ? { title: unknownHelp } : {})}` (unconditional title would spam ✓/✕ badges).
+  const helpSites = src.match(/t\("capabilityUnknownHelp"\)/g) || [];
+  if (helpSites.length < 3) {
+    failures.push(
+      `capability badge: expected t("capabilityUnknownHelp") at all 3 call sites, found ${helpSites.length}`
+    );
+  }
+  if (!/title:\s*unknownHelp/.test(src)) {
+    failures.push(
+      "capability badge: expected conditional title from unknownHelp on the badge span"
+    );
+  }
+
+  if (failures.length) {
+    for (const f of failures) fail(f);
+    console.error(
+      `[radar-sentinels] ${failures.length} broken invariant(s) in RadarCatalogTable.tsx`
+    );
+    process.exit(1);
+  }
+  console.log("[radar-sentinels] all invariants hold");
+}
+
+main();