Add LlmIntentClassifier and chat-to-proposal integration tests #716

Job	Run time
Dependency Review	5s
Workflow Lint	30s
OpenAPI Guardrail / OpenAPI Guardrail	35s
Backend Solution Regression	0s
Dependency Security Signals	0s
Load and Concurrency Harness	0s
Demo Director Smoke	0s
E2E Smoke	0s
	1m 10s

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