Script Sheet entity

A CanonicalScriptSheet is CanonicalEntity<"scriptsheet", ScriptSheetBody>: a name, one instruction (content),
an optional description, and optional samplers of the preset's own kind. It is ported from RoleCall's Script
Sheet, where a sheet is a preset row whose settings carry script_sheet: { version: 1, content }.

The writing family

Presets and Script Sheets are separate kinds that read one way: each kind's kind.ts gives asPreset, the preset
it sends (src/core/writing.ts). A promptbook will join the same way.

• One scene slot. The scene's Writing choice records the kind and the id (ChatPreset.kind, ChatStore rule 19),
  so one picker lists presets and sheets together. Loadouts and a character's starting setup carry the kind too.
• One reading. The turn reads a sheet through the family reader (presetReader in studio/scene-turn-load.ts)
  as its blocks, so assembly, Final Cut, the Booth and the trace treat it as a preset.
• One deck. The sheet kind joins the preset kind's Library deck (deck: "preset"), shown as "Writing".
• Export. A sheet is written by every platform's preset format as the preset it sends (formatsFor), except
  RoleCall, whose own Script Sheet format (formats/rolecall/script-sheet.ts) writes the sheet itself as RoleCall
  does: script_sheet at the top of the preset file beside the blocks it sends. It reads such files back as sheets,
  including the promptbook key of files saved before RoleCall's rename.
• Open as preset. The Workbench makes a new preset from a saved sheet: its blocks, samplers and words.

What a sheet sends

sheetPrompts in src/core/preset/script-sheet.ts lays the instruction out as ordinary blocks, in RoleCall's order:

• the instruction;
• the card's system prompt ({{charPrompt}});
• the context slots: description, personality, scenario, persona, lore, summary, memories and examples;
• the chat history;
• the card's post-history instructions ({{charInstruction}}), last.

The rules

Because that context is seated automatically, the instruction may not insert it itself: a context macro
({{description}}, {{lore}}, {{message_history}} and their other spellings) is refused, while {{char}} and
{{user}} are fine. The text must not be blank. The editors check this as you type. A turn with a stored sheet that
breaks it stops with RoleCall's words (the kind's sendProblem): "This Script Sheet has invalid instructions. Choose
another Script Sheet or Preset in Prompting." Reading checks only the shape and the 100,000-character cap, so a later
change to the rule never makes a stored sheet unreadable.

Editing

The kind's one editor is RoleCall's Script Sheet editor (src/ui/_shared/script-sheet-editor.tsx), opened from the
Prompting wing and, on the Workbench, with the description and samplers above it
(src/ui/apps/workbench/script-sheet-bench.tsx). The Library's "New script sheet" saves a blank sheet, which the
editor will not send until it has an instruction.