feat: add channel search matcher utility

frontend/src/lib/channel-search.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from "vitest";
+import { matchesChannelSearch } from "./channel-search";
+
+describe("matchesChannelSearch", () => {
+  it("matches case-insensitively", () => {
+    expect(matchesChannelSearch("#General", "gen")).toBe(true);
+  });
+
+  it("normalizes hash prefixes", () => {
+    expect(matchesChannelSearch("#devops", "#dev")).toBe(true);
+  });
+
+  it("returns true for empty queries", () => {
+    expect(matchesChannelSearch("#random", "")).toBe(true);
+  });
+
+  it("returns false when unmatched", () => {
+    expect(matchesChannelSearch("#backend", "frontend")).toBe(false);
+  });
+});

frontend/src/lib/channel-search.ts

@@ -0,0 +1,7 @@
+/** Channel search matching helpers. */
+export function matchesChannelSearch(name: string, query: string): boolean {
+  const n = name.toLowerCase().replace(/^#/, "");
+  const q = query.toLowerCase().trim().replace(/^#/, "");
+  if (!q) return true;
+  return n.includes(q);
+}