Add Azure AI Agents sample and test parity

[Mike Guo (guotuofeng)]

Summary

• add Java Azure AI Agents samples corresponding to portable Python scenarios
• add deterministic sync, async, voice, tool, streaming, routing, and multitool parity tests
• document required sample environment variables and telemetry dependencies
• defer realtime voice-session samples until Java exposes the required bidirectional API

Testing

• (288 tests, 0 failures/errors, 20 existing skips)
• Checkstyle: 0 violations
• Spotless: passed
• cspell: passed
• tracked and untracked whitespace checks: passed
• SpotBugs: configured to skip

🤖 Generated with Claude Code

[azure-pipelines]

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