chore(release): @openrouter/agent 0.5.0 (HITL tools)

[mattapperson]

Summary

Version-bump PR for @openrouter/agent from 0.4.0 → 0.5.0. Consumes the
pre-existing pending changeset and adds a new one for the HITL feature.

• Minor — Human-in-the-loop tool type (from feat(tools): add human-in-the-loop tool type #38, merged without a changeset): new HITLTool / HITLToolFunction, guards isHITLTool + isAutoResolvableTool, onToolCalled / onResponseReceived hooks, and a new 'awaiting_hitl' ConversationStatus. See packages/agent/CHANGELOG.md for the full entry.
• Patch — Stream detection regression coverage (from Use getReader for stream shape checks #34, via the pre-existing curvy-streams-watch changeset).

Code changes are limited to packages/agent/package.json (version) and
packages/agent/CHANGELOG.md. The .changeset/curvy-streams-watch.md file
is removed since changeset version consumed it.

Test plan

• CI: build / typecheck / lint / unit + e2e tests pass
• Confirm packages/agent/package.json is 0.5.0
• Confirm packages/agent/CHANGELOG.md includes both the HITL minor entry and the Use getReader for stream shape checks #34 patch entry
• On merge: tag + publish @openrouter/agent@0.5.0 via whatever release workflow the repo uses