fix: update Vertex AI Claude Sonnet 4.5 model identifier

- Add new model identifier 'claude-sonnet-4-5@20250929' as used by Vertex AI
- Keep deprecated 'claude-4.5-sonnet' for backward compatibility with deprecation comment
- Fixes issue where Vertex AI returns 404 for Claude Sonnet 4.5 requests

Fixes #8387

.tmp/review/Roo-Code

@@ -0,0 +1 @@
+Subproject commit 8dbd8c4b1b72fb48be3990a8e78285a787a1828c

.work/pr-8373/Roo-Code

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+Subproject commit b832e9253d2e62b4ce9e10a7a9a0f8d0263c3490

.work/reviews/Roo-Code

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+Subproject commit ea8420be8c5386d867fe6aa7b1f9756a44a3b5b1

packages/types/src/providers/vertex.ts

@@ -6,6 +6,7 @@ export type VertexModelId = keyof typeof vertexModels
 export const vertexDefaultModelId: VertexModelId = "claude-sonnet-4@20250514"
 
 export const vertexModels = {
+	// Deprecated: Use claude-sonnet-4-5@20250929 instead
 	"claude-4.5-sonnet": {
 		maxTokens: 8192,
 		contextWindow: 200_000,
@@ -18,6 +19,18 @@ export const vertexModels = {
 		cacheReadsPrice: 0.3,
 		supportsReasoningBudget: true,
 	},
+	"claude-sonnet-4-5@20250929": {
+		maxTokens: 8192,
+		contextWindow: 200_000,
+		supportsImages: true,
+		supportsComputerUse: true,
+		supportsPromptCache: true,
+		inputPrice: 3.0,
+		outputPrice: 15.0,
+		cacheWritesPrice: 3.75,
+		cacheReadsPrice: 0.3,
+		supportsReasoningBudget: true,
+	},
 	"gemini-2.5-flash-preview-05-20:thinking": {
 		maxTokens: 65_535,
 		contextWindow: 1_048_576,