chore(coding-agent): bump @anthropic-ai/claude-agent-sdk to 0.3.296
Bumps @anthropic-ai/claude-agent-sdk 0.3.292 -> 0.3.296 plus its 8 platform optionalDependencies (bun.lock). The releasability gate's "Claude Agent SDK currency" job fails on main while the pin trails the latest published release; node scripts/check-claude-code-model-support.mjs --sdk-currency passes locally after this bump. Release-blocking for 2026.10.12.
Summary by cubic
Bumps @anthropic-ai/claude-agent-sdk from 0.3.292 to 0.3.296 and its 8 platform-specific optional dependencies across bun.lock, package-lock.json, and the coding-agent install-lock, and raises the advertised claude-cli/2.1.x floor in anthropic-messages.ts to 2.1.296 to match. Adds changes.md and CHANGELOG.md entries. Unblocks the Claude Agent SDK currency releasability gate, which fails on main while the pin trails the latest release. Release-blocking for 2026.10.12.