Keep Set A (manual printtarg) and Set B (editor recipe layout) layout in sync

[itsab1989]

Split out from #89 (design fully settled there). Generators and patch count stay frozen; this is the layout-consistency layer so Set A and Set B can never disagree.

Background

A saved chart preset stores its layout in two places:

• Set A — data.printtarg_*: the literal printtarg flags the Create Chart → Manual tab reads/writes (instrument, paper, -t, -a scale, -M/-m margin, -h, -L, -P).
• Set B — editor_recipe: the New-Chart generator recipe (mode / colour-set checkboxes / sp params) plus a layout sub-block the editor / TI2-relayout path uses (patch_scale, margin, spacer_scale, spacer_mode, L, P, h, td, dpi, bit16, + instr/paper).

Nothing keeps the two in step. That's the root of the #89 confusion: a preset had editor_recipe.layout.td = true (Set B) while its printtarg block (Set A) read as plain -iCM — so the same preset rendered differently depending on which path read it. The functional break (Create Chart showing the wrong scale) is already fixed (beta.14 round-trips the effective TD layout into Set A). This issue is the robustness layer on top: make the two sets always carry the same layout so exported/shared .json files are self-consistent and any consumer reading Set A gets the right answer.

Goal

Set A and Set B always carry the same layout. Generators + count stay frozen.

Plan

1. Synced fields (option (a) — only the layout fields Set B already has):
patch_scale, margin, spacer_scale, spacer_mode, L, P, h, td, dpi, bit16 (+ instr / paper).
The td / h mode flags are included so a triple-density layout is unambiguous in Set A (triple density isn't a real printtarg flag — it expands to -ii1 -h only at render time — so td is the thing that actually marks it).

2. Sync points — all three write paths produce identical, consistent Set A + Set B:

• Edit Layout → Apply/Save → Overwrite → transfer the synced layout to the Create Chart manual tab (Set A) and the recipe (Set B).
• Edit Layout → Apply/Save → Save As → save a new preset carrying the synced effective layout in both Set A and Set B — exactly the same write path as Save Preset in the Create Chart manual tab (so the two routes produce identical preset files).
• Manual-tab printtarg change → on Generate, update Set B's layout from the manual widgets (layout fields only). Last edit wins.

3. Generators / patch count frozen:
Manual targen edits never rewrite Set B's generators or count. Editing targen + Generate writes a fresh .ti1 (Set B still recoverable via the New Chart window). Patch count is driven by the loaded .ti1 / preset / New-Chart output, and is only editable once targen editing is enabled (which writes a new .ti1).

4. Export:
The Create Chart export writes the effective layout (incl. td) into its printtarg block, so shared .json files are self-consistent.

5. Not in scope here: -r / -R / Shuffle / RANDOM_START → tracked in #90; folds into this sync once it lands.

Acceptance

• Editing scale/margin/density/etc. in the manual tab and generating updates Set B's layout to match (generators/count untouched).
• Editor Overwrite and editor Save As both leave Set A and Set B carrying identical layout; Save As produces a preset byte-equivalent to the manual-tab Save Preset for the same state.
• A triple-density preset is unambiguous from Set A alone (td present).
• Exported .json carries the effective layout in its printtarg block.
• New Chart window unaffected (no existing Set A to sync from at creation).

[itsab1989]

Implemented on branch feature/layout-ab-sync → v3.12.1-beta.1.

What changed

• A single source-of-truth mapping, recipe_layout_from_options(), turns the built layout (Set A) into the recipe's layout block (Set B).
• save_editor_meta() now reconciles editor_recipe.layout from the options the chart was actually built with — one chokepoint that covers Generate (Create Chart) and the editor's Save As / Overwrite paths.
• The editor's _reconcile_recipe_with_chart uses the same shared mapping.
• Manual Save Preset syncs the stored recipe's layout from the current manual widgets (_recipe_synced_to_manual), so a preset's two records match even if printtarg was edited after load.

Honoured from the settled plan

• Synced fields (option a): scale, margin, spacer scale/mode, L, P, h, td, dpi, bit16 (+ instrument/paper). ✅
• All three write paths (editor Overwrite, editor Save As, manual Save Preset) end up with consistent Set A + Set B. ✅
• Generators / colour-set params / source mode / patch count stay frozen. ✅
• Export (editor deliverable) writes the effective layout — covered, since its meta goes through the same reconcile. ✅
• -r / -R / Shuffle left untouched → still [Feature] Make Shuffle use printtarg's seeded randomisation (RANDOM_START) so -r / seed round-trips #90. ✅

Tests: new tests/test_layout_ab_sync.py (mapping, save-meta freezes generators + syncs layout, no caller mutation, manual-preset sync), plus updated recipe-persistence tests to the new contract. Full suite green (1154).

This is a beta on its own branch — not merged to master yet. Ready for Knut to test alongside the v3.12.0 line; I'll merge + cut the stable once it's confirmed.

[soul-traveller]

Verified that settings are same in all placed when changing parameters in Create Chart, and that they are saved as preset.