fix(javascript): preserve case-sensitive Unicode seed identity

Use NFC for case-sensitive feature seeds while preserving the existing explicit insensitive compatibility fold.

Validation: exact/substring/absent controls, fresh public CLI/MCP workflows and complete exact-head CI passed. Hosted CLI-worker failure and unchanged rerun results remain recorded in the PR.

Fixes #3314.

src/domain/javascript/javascriptFeatureSeed.unicode.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  APPLICATION_GRAPH_DIGESTS,
+  artifactEvidence,
+  fixtureNode,
+} from "./javascriptApplicationGraph.fixture.js";
+import { findApplicationFeatureSeeds } from "./javascriptFeatureSeed.js";
+
+const channelNode = (channel: string) =>
+  fixtureNode(
+    "ipc-channel",
+    {
+      strategy: "artifact-local-key",
+      stability: "artifact-version",
+      artifact_sha256: APPLICATION_GRAPH_DIGESTS.asar,
+      namespace: "electron-ipc",
+      key: channel,
+    },
+    channel,
+    { channel },
+    artifactEvidence(
+      APPLICATION_GRAPH_DIGESTS.asar,
+      "dist/preload.js",
+      "ast-static-analysis",
+    ),
+  );
+
+const nodes = [channelNode("ff"), channelNode("ff")] as const;
+
+const matchedNodeIds = (
+  value: string,
+  match: "exact" | "contains",
+  caseSensitive: boolean,
+) =>
+  findApplicationFeatureSeeds(nodes, {
+    kind: "channel",
+    value,
+    match,
+    case_sensitive: caseSensitive,
+  }).map(({ node_id }) => node_id);
+
+describe("application feature seed Unicode matching", () => {
+  it("keeps compatibility-distinct channels separate for exact case-sensitive seeds", () => {
+    expect(matchedNodeIds("ff", "exact", true)).toEqual([nodes[0].node_id]);
+    expect(matchedNodeIds("ff", "exact", true)).toEqual([nodes[1].node_id]);
+  });
+
+  it("does not compatibility-fold case-sensitive substring seeds", () => {
+    expect(matchedNodeIds("f", "contains", true)).toEqual([nodes[0].node_id]);
+  });
+
+  it("retains compatibility folding for explicit case-insensitive matching", () => {
+    expect(matchedNodeIds("FF", "exact", false)).toEqual(
+      nodes.map(({ node_id }) => node_id).sort(),
+    );
+  });
+});