feat(commit-message): add prompt template and generator service

Turns collected git context into a commit message. Part 2 of 4 for AI
commit-message generation; the VS Code wiring that calls this follows.

The prompt exposes the context as separate placeholders - `${branch}`,
`${recentCommits}`, `${changedFiles}` and `${diff}` - rather than one opaque
blob, so a user editing the prompt in Settings -> Prompts can reorder or drop any
of them independently. The diff is fenced in explicit markers and labelled as
repository content, since it reaches the model verbatim and can contain
instruction-like text.

`generator.ts` is deliberately free of VS Code: it takes git context and provider
settings and returns cleaned text, locating no repository and writing nowhere, so
it can be exercised without the extension host. Its tests load no `vscode` mock
at all, which is what keeps that honest.

An empty response is now a failure rather than a success. A model that answers
with nothing, or with an empty code fence, previously produced an empty message
that a caller would happily write over whatever the user had already typed.

`config.ts` resolves which profile to generate with. The chosen profile is only a
preference: a saved id outlives the profile it points at, and a profile can be
deleted between reading the state and looking it up, so both cases fall back to
the active configuration instead of stopping generation.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: Rafael-Silva-Oliveira

packages/types/src/global-settings.ts

@@ -235,6 +235,7 @@ export const globalSettingsSchema = z.object({
 	customSupportPrompts: customSupportPromptsSchema.optional(),
 	enhancementApiConfigId: z.string().optional(),
 	includeTaskHistoryInEnhance: z.boolean().optional(),
+	commitMessageApiConfigId: z.string().optional(),
 	historyPreviewCollapsed: z.boolean().optional(),
 	reasoningBlockCollapsed: z.boolean().optional(),
 	/**

packages/types/src/vscode-extension-host.ts

@@ -304,6 +304,7 @@ export type ExtensionState = Pick<
 	| "customModePrompts"
 	| "customSupportPrompts"
 	| "enhancementApiConfigId"
+	| "commitMessageApiConfigId"
 	| "customCondensingPrompt"
 	| "codebaseIndexConfig"
 	| "codebaseIndexModels"

src/core/webview/ClineProvider.ts

@@ -2461,6 +2461,7 @@ export class ClineProvider
 			customModePrompts,
 			customSupportPrompts,
 			enhancementApiConfigId,
+			commitMessageApiConfigId,
 			autoApprovalEnabled,
 			customModes,
 			experiments,
@@ -2619,6 +2620,7 @@ export class ClineProvider
 			customModePrompts: customModePrompts ?? {},
 			customSupportPrompts: customSupportPrompts ?? {},
 			enhancementApiConfigId,
+			commitMessageApiConfigId,
 			autoApprovalEnabled: autoApprovalEnabled ?? false,
 			customModes,
 			experiments: experiments ?? experimentDefault,
@@ -2852,6 +2854,7 @@ export class ClineProvider
 			customModePrompts: stateValues.customModePrompts ?? {},
 			customSupportPrompts: stateValues.customSupportPrompts ?? {},
 			enhancementApiConfigId: stateValues.enhancementApiConfigId,
+			commitMessageApiConfigId: stateValues.commitMessageApiConfigId,
 			experiments: stateValues.experiments ?? experimentDefault,
 			autoApprovalEnabled: stateValues.autoApprovalEnabled ?? false,
 			customModes,

src/core/webview/__tests__/ClineProvider.spec.ts

@@ -1226,6 +1226,47 @@ describe("ClineProvider", () => {
 		})
 	})
 
+	describe("commit message model selection is included in state", () => {
+		// Both paths matter: the webview reads the posted state to show the current selection, and
+		// the generator reads getState() to pick a profile. Dropping either one makes a saved
+		// selection look like it reverted.
+		it("getStateToPostToWebview returns the saved commitMessageApiConfigId", async () => {
+			await provider.resolveWebviewView(mockWebviewView)
+			await provider.contextProxy.setValue("commitMessageApiConfigId", "config-2")
+
+			const state = await provider.getStateToPostToWebview()
+
+			expect(state.commitMessageApiConfigId).toBe("config-2")
+		})
+
+		it("getStateToPostToWebview leaves commitMessageApiConfigId unset when no profile is chosen", async () => {
+			await provider.resolveWebviewView(mockWebviewView)
+			await provider.contextProxy.setValue("commitMessageApiConfigId", undefined)
+
+			const state = await provider.getStateToPostToWebview()
+
+			expect(state.commitMessageApiConfigId).toBeUndefined()
+		})
+
+		it("getState returns the saved commitMessageApiConfigId", async () => {
+			await provider.resolveWebviewView(mockWebviewView)
+			await provider.contextProxy.setValue("commitMessageApiConfigId", "config-2")
+
+			const state = await provider.getState()
+
+			expect(state.commitMessageApiConfigId).toBe("config-2")
+		})
+
+		it("getState leaves commitMessageApiConfigId unset when no profile is chosen", async () => {
+			await provider.resolveWebviewView(mockWebviewView)
+			await provider.contextProxy.setValue("commitMessageApiConfigId", undefined)
+
+			const state = await provider.getState()
+
+			expect(state.commitMessageApiConfigId).toBeUndefined()
+		})
+	})
+
 	it("getStateToPostToWebview passes through defined diffFuzzyThreshold value", async () => {
 		await provider.resolveWebviewView(mockWebviewView)
 		await provider.contextProxy.setValue("diffFuzzyThreshold", 0.5)

src/i18n/locales/ca/common.json

@@ -40,6 +40,7 @@
 		"update_support_prompt": "Failed to update support prompt",
 		"reset_support_prompt": "Failed to reset support prompt",
 		"enhance_prompt": "Failed to enhance prompt",
+		"commit_message_empty_response": "The model returned an empty commit message.",
 		"get_system_prompt": "Failed to get system prompt",
 		"search_commits": "Failed to search commits",
 		"save_api_config": "Failed to save api configuration",