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.test.ts

@@ -0,0 +1,123 @@
+import { describe, expect, test } from "bun:test"
+import { normalizeModel, normalizeModelID } from "./model-normalization"
+
+describe("normalizeModel", () => {
+	describe("#given undefined input", () => {
+		test("#when normalizeModel is called with undefined #then returns undefined", () => {
+			// given
+			const input = undefined
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBeUndefined()
+		})
+	})
+
+	describe("#given empty string", () => {
+		test("#when normalizeModel is called with empty string #then returns undefined", () => {
+			// given
+			const input = ""
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBeUndefined()
+		})
+	})
+
+	describe("#given whitespace-only string", () => {
+		test("#when normalizeModel is called with whitespace-only string #then returns undefined", () => {
+			// given
+			const input = "   "
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBeUndefined()
+		})
+	})
+
+	describe("#given valid model string", () => {
+		test("#when normalizeModel is called with valid model string #then returns same string", () => {
+			// given
+			const input = "claude-3-opus"
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBe("claude-3-opus")
+		})
+	})
+
+	describe("#given string with leading and trailing spaces", () => {
+		test("#when normalizeModel is called with spaces #then returns trimmed string", () => {
+			// given
+			const input = "  claude-3-opus  "
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBe("claude-3-opus")
+		})
+	})
+
+	describe("#given string with only spaces", () => {
+		test("#when normalizeModel is called with only spaces #then returns undefined", () => {
+			// given
+			const input = "     "
+
+			// when
+			const result = normalizeModel(input)
+
+			// then
+			expect(result).toBeUndefined()
+		})
+	})
+})
+
+describe("normalizeModelID", () => {
+	describe("#given model with dots in version numbers", () => {
+		test("#when normalizeModelID is called with claude-3.5-sonnet #then returns claude-3-5-sonnet", () => {
+			// given
+			const input = "claude-3.5-sonnet"
+
+			// when
+			const result = normalizeModelID(input)
+
+			// then
+			expect(result).toBe("claude-3-5-sonnet")
+		})
+	})
+
+	describe("#given model without dots", () => {
+		test("#when normalizeModelID is called with claude-opus #then returns unchanged", () => {
+			// given
+			const input = "claude-opus"
+
+			// when
+			const result = normalizeModelID(input)
+
+			// then
+			expect(result).toBe("claude-opus")
+		})
+	})
+
+	describe("#given model with multiple dot-numbers", () => {
+		test("#when normalizeModelID is called with model.1.2 #then returns model-1-2", () => {
+			// given
+			const input = "model.1.2"
+
+			// when
+			const result = normalizeModelID(input)
+
+			// then
+			expect(result).toBe("model-1-2")
+		})
+	})
+})