feat: Notion-style implicit toggle body + debounced saves

[rikiyanai]

• Toggle body is now implicit: everything under a title down to the next toggle (or EOF) collapses — anything typed/pasted underneath is automatically inside. Ledger maintains only title lines (shift / re-anchor / dedupe); the boundary bug class is gone.
• Title-touching edits re-anchor instead of dropping the toggle.
• Saves coalesced to 1/sec (was a full-canvas write per keystroke), flushed on quit/Clear/terminate.

Verified: 8 new-model ledger replica cases + full headless suite. Root-cause trail in docs/FAILURE_LOG.md (2026-07-21).

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Note

Medium Risk
Toggle fold/containment logic is substantially reworked (data loss risk if debounced save isn’t flushed before a hard kill); debounced saves are mitigated by flush on normal quit/terminate.

Overview
Toggle lists now match Notion’s container model: bodyEndLine is removed from ToggleEntry, and collapse covers everything under a title until the next toggle’s title or EOF via bodyEnd(forToggleAt:). Create/remove/flip, fold rendering, caret containment, and context menu all use that implicit range; nested toggles split at a new title instead of flattening overlaps.

The edit ledger only tracks title lines—shift when edits are at/above the title, re-anchor when the title line is edited (instead of dropping the toggle), dedupe duplicate title lines. Legacy toggles.json with bodyEndLine still decodes.

Canvas persistence no longer writes on every keystroke: scheduleSave() debounces to once per second; flushSave() runs on Clear, Quit, and applicationWillTerminate.

docs/FAILURE_LOG.md documents the implicit-body model, re-anchoring, and performance fix.

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Toggles persist ahead of notes

High Severity

textDidChange still writes toggles.json on every edit while notes.txt is deferred by up to one second via scheduleSave. If the process exits before a flush (crash, force quit, kill), disk toggles match the live buffer but the canvas file does not, so reload pairs stale text with shifted title-line metadata.

Additional Locations (1)

• TermiNotesAppKit.swift#L393-L398

 

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