Accept any openai>=2.45.0 so the integration loads on HA 2026.10

Home Assistant 2026.10 pins openai==3.10.0 in its package constraints, so the
manifest's exact openai==2.45.0 can no longer be installed and setup fails:

  Setup failed for custom integration 'openai_compatible': Requirements for
  openai_compatible not found: ['openai==2.45.0'].

The requirement is now a floor. Each Home Assistant release then installs the
openai it pins: 2.45.0 on 2026.9, 3.10.0 on 2026.10.

The vendored code needs no change for 3.x. The only breaking change in openai
3.0 is HTTPX2 as the default client, and passing Home Assistant's legacy httpx
client is still supported at runtime, which is how core's own integration
handles it. Every openai import in the integration resolves on 3.10.0, and the
suite passes against it on the 2026.10.0 test harness (170 passed).
requirements_test.txt now pins 3.10.0 so CI tests what current Home Assistant
ships.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0123XQr8dh5RnFLnECHPVNrd

custom_components/openai_compatible/manifest.json

@@ -17,7 +17,7 @@
   "iot_class": "cloud_polling",
   "issue_tracker": "https://github.com/adamjs83/ha-openai-compatible/issues",
   "requirements": [
-    "openai==2.45.0"
+    "openai>=2.45.0"
   ],
   "version": "0.2.0"
 }