Feature: host-side parameter presets with reproducible run configuration #63

Goal

Allow users to save, reapply, export and share tool parameter presets across sessions without making each application implement settings persistence. Treat this as a host/runtime capability, not a per-parameter manifest marker.

Design

• Preserve the app/tool ID, manifest version or schema fingerprint, parameter names and values, and which optional inputs are deliberately unset. Reuse existing run-record and Copy as command infrastructure.
• Keep image-layer identities, ROI selections and host-local paths separate from portable numeric/text settings; clearly indicate inputs requiring reselection on another machine.
• Detect renamed or removed parameters and incompatible schema versions; ask for explicit resolution instead of silently using defaults.
• Do not serialize credentials or sensitive application-local state into shareable presets without explicit consent.
• Support save/load in Napari first, then Fiji and QuPath with corresponding UX.

Acceptance criteria

• A preset round-trips with exact scalar values, units and nullable state.
• Reloading a preset after a schema change reports incompatible fields and does not run until resolved.
• Sharing across hosts reproduces scientific parameters while prompting for host-specific image/file bindings.
• Regression tests cover repeated runs, migration and corrupted preset files.

Priority: Medium; can follow stable form generation.