Fix screenshot frozen-entry crash and prepare v0.1.6

[yvette-carlisle]

Summary

• avoid frozen toolbar hover hit-testing during first frozen-frame installation
• share one explicit toolbar hit-test path for toolbar and annotation style hover state
• bump workspace/package release metadata and docs to v0.1.6

Root cause

Crash reports from /Applications/Rsnap.app v0.1.5 point to CaptureHostView.refreshHoveredToolbarAction(for:) during installFrozenFirstFrame. The intermittent part matches release timing and pointer position: first frozen-frame presentation could synchronously rebuild toolbar layout and style hover state while the toolbar was not yet fully settled.

Validation

• cargo make checks
• cargo make fmt-check
• cargo make test-host-reset
• cargo make test-macos-native-host-stage
• cargo make test-macos-native-host
• VISUAL_CONTRACT_CASES=liquid REPEATED_DRAG_FREEZES=6 REPEATED_CLICK_FREEZES=0 VISUAL_PROBE_ALL_DRAGS=0 APP_POST_VERIFY_SETTLE_S=0 POST_FREEZE_SETTLE_S=0.12 POST_CLOSE_SETTLE_S=0.12 ./scripts/smoke/native-visual-contract-macos.sh
• ./scripts/perf/local.sh
• git diff --check

Release validation note

The exact local desktop aggregators are currently blocked in this Codex session by the local ScreenCaptureKit/automation environment: SCShareableContent returns displayCount=0 and the automated Option-X path does not enter capture telemetry for both the staged app and /Applications/Rsnap.app. No new RsnapNativeHost crash reports were produced during those attempts.