The watch callback forwarded every FS event, including the pure reads the
viewer's own GET /api/file produces (IN_ACCESS / IN_CLOSE_NOWRITE on Linux):
each silent reload re-triggered the watcher, looping at ~1 Hz. For PDFs every
iteration minted a new blob URL and re-assigned iframe.src, which re-runs
Chrome's whole PDF viewer (the flicker) and pushes a joint session-history
entry (the back button buried under hundreds of blob: entries).
- file_watch: forward an event only when the content version (mtime_ns, len)
actually moved; drop Access events outright, stat-compare the rest.
- viewer: render pdf/latex/svg previews in a keyed() iframe — a fresh
element's first navigation replaces its history slot instead of pushing.
- GET /api/file returns ETag (mtime+size) + X-Writable on disk files;
PUT /api/file accepts optional if_match -> 409 Conflict on stale version
(last-write-wins preserved when omitted), echoes the new ETag
- FileViewerBase: View | Edit tabs for .md when the caller can write;
source textarea with Save/Cancel, live preview while editing
- Watcher no longer clobbers the buffer mid-edit: while editing with
unsaved changes it probes the server ETag and only raises a conflict
when the remote actually moved on (own-save echo is ignored)
- Conflict banner: Reload remote | Copy mine, then reload | Overwrite
- i18n (en/it/fr) + CSS; docs/projects.md updated
dguiducci