fix(amp): preserve lowercase glob tool name

[edlsh]

Summary

• normalize known Amp tool names in rewritten responses
• preserve the lowercase glob name that Amp expects instead of rewriting it to Glob
• add regression coverage for normalized and untouched tool names

Testing

• go test ./internal/api/modules/amp
• go test ./...
• go build -o test-output ./cmd/server && rm test-output

[gemini-code-assist]

Code Review

This pull request introduces tool name normalization to ensure compatibility with Amp's case-sensitive tool whitelist. It adds a mapping of canonical tool names and a function to update tool names in both streaming and non-streaming API responses. Unit tests were added to verify the normalization logic. Feedback was provided regarding an optimization in the streaming logic to reduce redundant JSON parsing when accessing content_block fields.

[gemini-code-assist]

The code performs redundant JSON parsing by calling gjson.GetBytes twice for the same content_block object. It is more efficient to retrieve the content_block once and then use Get on the resulting gjson.Result to access its fields. This is particularly relevant in streaming mode where this logic is executed for every chunk.

	// Streaming: content_block.name in content_block_start events
	contentBlock := gjson.GetBytes(data, "content_block")
	if contentBlock.Get("type").String() == "tool_use" {
		name := contentBlock.Get("name").String()