Rule editor: extended JsonLogic ops + rich action forms (follow-up #833)

[rubenvdlinde]

Deferred from #833 (closes that issue, shipped via PR #873).

Visual JsonLogic condition tree + action-specific parameter form shipped with the core 15 action types and basic ops. Missing:

• Extended JsonLogic ops: `map`, `reduce`, `filter`, `some`, `all`, `none`, `merge` (array reducers). Currently only scalar + comparison ops exposed.
• Rich action forms for the 5 action types that still render as raw JSON textareas (`saveObject`, `updateObject`, `createObject`, `addArrayItem`, `removeArrayItem`). Each needs a register/schema picker + a per-field input map.
• Drag-reorder between sibling action steps.

Acceptance

• All JsonLogic 2.0 array operators selectable from the visual tree
• The 5 object-mutation actions render with proper field pickers
• Drag handle on action rows persists new order on save

[rubenvdlinde]

Closed by PR #908.