bc0b258e04
Sidecars (*.comments.json) stay out of the index and listings and follow rename and delete of their note; end-to-end comments test over a stub server (Ana comments and mentions Bob, Bob resolves, second sync changes nothing); viewer extension tables gain ico, ogv, 3gp, opus, aac; annotate crate: Edit::Replace for undoable text moves and edits, line items carry an arrow flag; syntax test fixed (TeX is a bundled grammar). Built by MiniMax M3.1 Flash and Claude Sonnet; verified with the full cargo xtask ci on the combined tree (4422 tests, clippy -D warnings, layers, tree, i18n). Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>