Longer Sessions, Smoother Migration, and Permissions Fixes

Note: To get the latest 1.0.x release, download it directly from kiro.dev/downloads. Auto-updates are being rolled out gradually to users.

This release resolves context compaction issues that caused premature summarization and fatal crashes on long sessions. Session migration becomes a user-initiated action with file checkpoints preserved, hooks auto-migrate from the legacy format, and several permissions and MCP reliability issues are fixed.