Text-substitution autoformat authority

Question

What should Plate treat as the authority stack for text-substitution autoformat families such as smart quotes, punctuation replacement, arrows, legal symbols, fractions, and other symbol shorthands?

Current answer

This family is weaker than block shorthand or markdown-delimiter autoformat.

Current evidence is:

strong for current Plate package behavior:
- @platejs/autoformat ships the substitution tables
- tests cover punctuation, legal symbols, smart quotes, division/per-mille, fractions, and undo-on-delete
decent for mainstream typing norms:
- smart quotes
- em dash
- ellipsis
- angle quotes
thin for direct cross-editor product authority on:
- arrows
- legal symbols
- comparison/equality/operator symbol shorthands
- fraction replacements
- superscript/subscript unicode shorthand

The current usable authority split is:

smart quotes, em dash, ellipsis, and angle quotes:
- mainstream typographic norms + current Plate tests are enough to spec
arrows, legal symbols, fractions, operator replacements, and unicode super/sub shorthand:
- current Plate contract is explicit
- stronger cross-editor authority is still thin

Why this matters

Without this gap staying explicit, it is too easy to pretend:

a local substitution table is universal editor truth
markdown-native shorthand and plain symbol substitution belong to one family

They do not.

Remaining gap

The unresolved question is how much of this family should be justified by:

mainstream typing norms
local current Plate contract
future stronger Typora / Obsidian / Milkdown evidence

until that evidence is compiled, this family should stay explicit as a profile-adjacent current contract with thinner external grounding than block or mark shorthand