[HTTPXodus] migrate httpx to httpx2 (hard switch; closes #1856)

[ProgrammerPlus1998]

Closes #1856

🏷️ Part of HTTPXodus — a community effort to help major Python projects plan their path off the stalled httpx stable line onto httpx2, the actively maintained fork by Pydantic Services.

What this PR does

Complete hard switch from httpx to httpx2:

• Removes every try/except ImportError dual-import block and import httpx2 as httpx aliasing — direct import httpx2 in media.py, _task_manager/media_manager.py, _utils/request.py, _client/client.py, _client/resource_manager.py, and api/ modules
• Test suite converted too (test_media_manager, test_openai, test_resource_manager, test_additional_headers_simple, support/api_wrapper, ...)
• pyproject.toml: drops httpx>=0.15.4,<1.0; httpx2>=2.12.0 unconditional (requires-python is already >=3.10)
• logger.py noise-reduction logger name follows the library rename: "httpx" → "httpx2"

Generated code

langfuse/api/ is generated from the API spec. The conversion is mechanical and API-identical, but the switch should also land in the generator/templates so the next regeneration doesn't overwrite it.

Test results

• pytest tests/unit: 632 passed; the 39 failures + 18 errors are identical on the base commit (verified by control run) — all are "Langfuse client is not initialized"-type environment issues, zero migration regressions

Notes for reviewer

• ⚠️ TLS behavior change: httpx2 verifies TLS against the OS trust store (via truststore) instead of the bundled certifi. Deployments that relied on certifi's CA bundle may need SSL_CERT_FILE / SSL_CERT_DIR after the switch. Worth a line in the changelog.

Happy to revise per review — and equally happy to close this PR if the maintainers would rather wait for httpx 1.0 stable. 🙏

[claude]

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[greptile-apps]

Lockfile Is Stale

This adds httpx2 without regenerating uv.lock. The locked langfuse dependency metadata still contains only httpx, while every CI job installs dependencies with uv sync --locked. As a result, CI fails during dependency installation before linting, type checking, or tests can run. Please regenerate and commit the lockfile.

Prompt To Fix With AI

This is a comment left during a code review.
Path: pyproject.toml
Line: 12

Comment:
**Lockfile Is Stale**

This adds `httpx2` without regenerating `uv.lock`. The locked `langfuse` dependency metadata still contains only `httpx`, while every CI job installs dependencies with `uv sync --locked`. As a result, CI fails during dependency installation before linting, type checking, or tests can run. Please regenerate and commit the lockfile.

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