feat(dashboard): text filter for Overview workplans chart

Add a search field next to the Workplans by Repository mode selector so
operators can narrow large lists by title, repo, domain, filename, or owner.

dashboard/test/workplan-search.test.mjs

@@ -0,0 +1,42 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import {readFileSync} from "node:fs";
+import {dirname, join} from "node:path";
+import {fileURLToPath} from "node:url";
+
+import {workplanMatchesSearch} from "../src/components/workplan-search.js";
+
+const root = dirname(fileURLToPath(import.meta.url));
+const indexMd = readFileSync(join(root, "../src/index.md"), "utf-8");
+
+const sample = {
+  id: "abc-123",
+  title: "Overview Workstream Stage Counts",
+  repo_label: "state-hub",
+  domain: "infotech",
+  workplan_filename: "STATE-WP-0057-overview-workstream-stage-counts.md",
+  owner: "codex",
+};
+
+test("empty query matches all workplans", () => {
+  assert.equal(workplanMatchesSearch(sample, ""), true);
+  assert.equal(workplanMatchesSearch(sample, "   "), true);
+  assert.equal(workplanMatchesSearch(sample, null), true);
+});
+
+test("matches title, repo, domain, filename, owner, and id", () => {
+  assert.equal(workplanMatchesSearch(sample, "stage counts"), true);
+  assert.equal(workplanMatchesSearch(sample, "STATE-HUB"), true);
+  assert.equal(workplanMatchesSearch(sample, "Infotech"), true);
+  assert.equal(workplanMatchesSearch(sample, "wp-0057"), true);
+  assert.equal(workplanMatchesSearch(sample, "codex"), true);
+  assert.equal(workplanMatchesSearch(sample, "abc-123"), true);
+  assert.equal(workplanMatchesSearch(sample, "railiance"), false);
+});
+
+test("overview chart wires the text filter into Workplans by Repository", () => {
+  assert.match(indexMd, /workplanMatchesSearch/);
+  assert.match(indexMd, /ws-search-input/);
+  assert.match(indexMd, /Filter by title, repo, domain/);
+  assert.match(indexMd, /## Workplans by Repository/);
+});