Feat(AI): Create transactions in AI agent frameworks if no transaction is running.

[constantinius]

This includes:

• Anthropic: message.create
• Langchain: invoke_agent spans
• OpenAI Agents: invoke_agent spans + agent workflow (which was already like that)

Closes https://linear.app/getsentry/issue/TET-1048/auto-wrap-gen-aiinvoke-agent-if-no-transaction-in-scope

[linear]

TET-1048 Auto-wrap gen_ai.invoke_agent if no transaction in scope

[codecov]

Codecov Report

❌ Patch coverage is 88.23529% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.56%. Comparing base (18d3899) to head (3548f81).
⚠️ Report is 2 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
sentry_sdk/integrations/langchain.py	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4758      +/-   ##
==========================================
- Coverage   84.57%   84.56%   -0.01%     
==========================================
  Files         158      158              
  Lines       16480    16484       +4     
  Branches     2855     2855              
==========================================
+ Hits        13938    13940       +2     
- Misses       1695     1697       +2     
  Partials      847      847              

Files with missing lines	Coverage Δ
sentry_sdk/ai/utils.py	77.77% <100.00%> (+5.05%)	⬆️
sentry_sdk/integrations/anthropic.py	86.59% <100.00%> (ø)
...integrations/openai_agents/spans/agent_workflow.py	100.00% <100.00%> (ø)
...k/integrations/openai_agents/spans/invoke_agent.py	87.50% <100.00%> (+0.40%)	⬆️
sentry_sdk/integrations/openai_agents/utils.py	83.78% <ø> (-0.84%)	⬇️
sentry_sdk/integrations/langchain.py	68.99% <60.00%> (-0.10%)	⬇️

... and 2 files with indirect coverage changes

[antonpirker]

Looks good. Thanks for fixing!