Fix 9 failing live integration tests (memory leaks + missing status check)

[tomjnsn]

Problem

9 live integration tests fail consistently due to memory leaks detected by testing.allocator (GPA) and a missing HTTP status check.

Failing Tests

#	Test	Root Cause
1	Azure streamText	Missing defer deinit in test
2	Anthropic streamText	Missing defer + provider leaks streaming IDs
3	Google streamText	Missing defer + provider leaks text copies
4	OpenAI generateObject	generateObject passes base allocator to doGenerate
5	Anthropic generateObject	Same as #4
6	Google generateObject	Same as #4
7	Google streamObject	streamObject passes base allocator to doStream
8	Google embed	No HTTP status code check → parses error body as response
9	Google embedMany	Same as #8

Fix Summary

1. Add missing defer http_client.deinit() and defer provider.deinit() to all streamText tests
2. Anthropic streaming: use stream_allocator for ephemeral IDs instead of result_allocator
3. Google streaming: use request_allocator for text/function call copies instead of result_allocator
4. generateObject: pass arena_allocator to doGenerate, dupe result strings to base allocator
5. streamObject: pass arena_allocator to doStream
6. Google embedding: add HTTP status code check before parsing response body