fix: add thread-safe accessor methods to mockRecorderClient

[mtojek]

Fixes #59

Fixes data race in bridge_integration_test.go where test code was directly accessing mockRecorderClient fields (tokenUsages, userPrompts, toolUsages, interceptions) without holding the mutex, while the Record* methods were modifying these fields under the mutex.

Changes

Added four new accessor methods that return copies of the recorded data under mutex protection:

• RecordedTokenUsages()
• RecordedPromptUsages()
• RecordedToolUsages()
• RecordedInterceptions()

All direct field accesses in tests have been replaced with calls to these new thread-safe accessor methods.

Testing

All tests pass with -race flag enabled:

go test -race ./...
ok  	github.com/coder/aibridge	1.335s
ok  	github.com/coder/aibridge/buildinfo	1.014s
ok  	github.com/coder/aibridge/mcp	1.037s
ok  	github.com/coder/aibridge/utils	1.016s

Non-agent testing

while true; do go test -timeout 600s -run ^TestAnthropicInjectedTools$ github.com/coder/aibridge -count=500 -race -parallel=8; done

[dannykopping]

LGTM with a note about safety