Port the ten backend, automation and test paths from #5493 by
@jonathanwxh-cell, pinned at 43920ab780.
Keep its original CSH codec, bounded preset reader and protection tests.
The prerequisite's UI, translation and parity-document changes are excluded.
Adapt ShapePreset construction to retain the exact source identifier. Empty
identifiers remain anonymous presets; repeated identifiers resolve when their
geometry is identical and refuse resolution when it conflicts. Add one
import-to-ATN Shape Blur regression and document the source attribution.
Original contribution: https://github.com/storytold/photocraft/pull/5493
Source-only integration; compilation and combined runtime validation remain.
yoriswind
c78b84a1cd