refactor(shared): deduplicate model resolution utility functions

Extract normalizeModel() (3 identical copies) and normalizeModelID()
(2 identical copies) into canonical src/shared/model-normalization.ts.
Delete dead-end duplicate model-name-matcher.ts. Update all consumers.

src/shared/model-normalization.ts

@@ -0,0 +1,8 @@
+export function normalizeModel(model?: string): string | undefined {
+	const trimmed = model?.trim()
+	return trimmed || undefined
+}
+
+export function normalizeModelID(modelID: string): string {
+	return modelID.replace(/\.(\d+)/g, "-$1")
+}