Problem: nothing fuzzed project files. The hand-written .ecprojx XML reader
recursed once per nested <arr>/<obj> with no limit, so a deeply nested file
overflowed the stack and aborted the app instead of failing to open.
Fix: a dependency-free, deterministic, seeded mutation fuzzer for File > Open
(JSON and XML seeds from the demo, byte and JSON-structure mutations, the real
file.open path, first queries and a thumbnail render; each input under
catch_unwind with a deadline; bounded for cargo test, longer runs via env
vars). The XML reader now stops at the JSON reader's 128-level limit, with a
regression test.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>