fix(artifacts): match drifted update id by normalized key before latest-artifact fallback

Addresses review: with multiple artifacts, a case/whitespace-drifted id (e.g. 'App' for 'app') was attached to the most-recently-created artifact instead of the one it meant. Now try a normalized (trim+lowercase) id match first; fall back to the latest only when there's no unambiguous normalized match.

Author: gary149

src/lib/utils/artifacts.spec.ts

@@ -330,6 +330,22 @@ describe("collectArtifacts", () => {
 		expect(registry.byMessageOp.get("m3:0")).toEqual({ identifier: "second", version: 2 });
 	});
 
+	it("prefers a normalized identifier match over the latest artifact for drifted ids", () => {
+		const registry = collectArtifacts([
+			msg("m1", `<artifact identifier="app" type="html" title="App">alpha</artifact>`),
+			msg("m2", `<artifact identifier="chart" type="html" title="Chart">bravo</artifact>`),
+			msg(
+				"m3",
+				`<artifact identifier="App" type="update"><old_str>alpha</old_str><new_str>gamma</new_str></artifact>`
+			),
+		]);
+		// "App" drifts from "app" by case, so it links there — not the latest ("chart")
+		expect(registry.artifacts.get("app")?.versions).toHaveLength(2);
+		expect(registry.artifacts.get("app")?.versions[1]?.content).toBe("gamma");
+		expect(registry.artifacts.get("chart")?.versions).toHaveLength(1);
+		expect(registry.byMessageOp.get("m3:0")).toEqual({ identifier: "app", version: 2 });
+	});
+
 	it("applies streaming update pairs progressively", () => {
 		const registry = collectArtifacts(
 			[

src/lib/utils/artifacts.ts

@@ -329,6 +329,11 @@ export function artifactOpKey(messageId: Message["id"], opIndex: number): string
 	return `${messageId}:${opIndex}`;
 }
 
+/** Case/whitespace-insensitive identifier key, for tolerant update linking. */
+function normalizeIdentifier(id: string): string {
+	return id.trim().toLowerCase();
+}
+
 /**
  * Walk the active conversation path and fold artifact operations into
  * versioned artifacts. Updates apply onto the latest version of the same
@@ -395,12 +400,18 @@ export function collectArtifacts(
 			// update op
 			// Models sometimes rename the identifier when editing (e.g. green-button ->
 			// blue-button) or drift its case/whitespace, which would orphan the update as a
-			// dead "couldn't be linked" card. An update is by definition an edit to existing
-			// content, so when the id doesn't match an existing artifact, link to the
-			// most-recently-created one (the Map preserves insertion order). Only leave a
-			// disabled card when there's genuinely nothing to link to.
+			// dead "couldn't be linked" card. When the id doesn't match an existing artifact,
+			// first try a normalized (case/whitespace-insensitive) match so a drifted id hits
+			// the artifact it meant; otherwise fall back to the most-recently-created one (an
+			// update is by definition an edit to existing content, and the Map preserves
+			// insertion order). Only leave a disabled card when there's nothing to link to.
 			if (!artifact && artifacts.size > 0) {
-				artifact = [...artifacts.values()].at(-1);
+				const wanted = normalizeIdentifier(op.identifier);
+				const normalizedMatches = [...artifacts.values()].filter(
+					(a) => normalizeIdentifier(a.identifier) === wanted
+				);
+				artifact =
+					normalizedMatches.length === 1 ? normalizedMatches[0] : [...artifacts.values()].at(-1);
 			}
 			const base = artifact?.versions.at(-1);
 			if (!artifact || !base) {