feat: support history_config and bump google-genai dependency to <3

Support history_config parameter in LiveConnectConfig and log when initial_history_in_client_content is configured. Upgraded google-genai upper bound to <3 to allow v2 releases.

TAG=agy
CONV=a0ce9f11-6461-41a0-b904-f01ed1aa9f10

Change-Id: I5f4f2138ea6282803414459f1d868fa9e813a415

Author: wukath

pyproject.toml

@@ -51,7 +51,7 @@ dependencies = [
   "google-cloud-spanner>=3.56,<4",                          # For Spanner database
   "google-cloud-speech>=2.30,<3",                           # For Audio Transcription
   "google-cloud-storage>=2.18,<4",                          # For GCS Artifact service
-  "google-genai>=1.72,<2",                                  # Google GenAI SDK
+  "google-genai>=1.72,<3",                                  # Google GenAI SDK
   "graphviz>=0.20.2,<1",                                    # Graphviz for graph rendering
   "httpx>=0.27,<1",                                         # HTTP client library
   "jsonschema>=4.23,<5",                                    # Agent Builder config validation