feat(agent-sdk): migrate to 0.3.258 and support message queues

[srothgan]

Summary

• Upgrade both Agent SDK package surfaces and the bridge version guard to 0.3.258, use summary-only context polling, and preserve the snapshotted system prompt across resume.
• Add an SDK-correlated active-turn user-message queue with bounded host projection, exactly-once transcript insertion, payload recovery, Esc reconciliation, and compact TUI previews.
• Add MCP resource links and ambient-task metadata end to end, harden structured Write output, extend REPL/Artifact/ScheduleWakeup rendering, and reconcile final background Bash and authoritative MCP status notifications.

Why

Agent SDK 0.3.258 adds correlation and result metadata that let the host accept messages during an active turn and present richer task and tool results. The migration also changes several output contracts, including nullable Write originals, which require host-side compatibility handling to avoid stale tasks or misleading diffs.

Closes #

Validation

• Automated: npm.cmd --prefix agent-sdk test (385 tests), npm.cmd --prefix agent-sdk run lint, npm.cmd --prefix agent-sdk run knip, npm.cmd --prefix agent-sdk run audit, npm.cmd pack --dry-run, cargo fmt --all -- --check, cargo check --offline, cargo clippy --all-targets --all-features --offline -- -D warnings, and cargo test --offline.
• Manual: Active-turn queuing was exercised in depth, including SDK receipt, queue removal, and transcript insertion.
• Screenshot/video: Not attached.

Notes

• Breaking changes: None expected.
• Docs updated: The local migration analysis is intentionally not part of this PR.
• Governance/release impact: Ships the Agent SDK and bundled Claude Code parity update together with the host features it enables.
• Remaining smoke coverage: The less common MCP resource-link, managed-model, background Bash, and structured Artifact/REPL/ScheduleWakeup surfaces are covered by automated fixtures but were not all exercised interactively.