fix: handle invalid Windows save paths

docs/ABSTRACTIONS.md

@@ -266,6 +266,7 @@ Tolaria separates **display title** from the file identifier:
 - **Explicit filename actions** (`rename_note`): breadcrumb rename/sync actions stage crash-safe note renames through a hidden `.tolaria-rename-txn/` transaction directory, recover unfinished renames on the next vault scan, update wikilinks across the vault, and surface any failed backlink rewrites instead of silently reporting partial success. The editor body remains the title editing surface.
 - **Unicode-aware note stems** (`src/utils/noteSlug.ts`, `vault/rename.rs`): frontend and backend slugging preserve Unicode letters/digits in note filenames, untitled-rename detection, and fallback wikilink targets while still collapsing symbol-only titles to `untitled`.
 - **Portable filename validation** (`vault/filename_rules.rs`): note filenames, folder names, and custom view filenames all reject Windows-reserved device names, invalid characters, and trailing dot/space suffixes so a vault created on macOS/Linux still clones and syncs cleanly on Windows.
+- **Recoverable save failures** (`useEditorSave`, `vault/file.rs`): invalid platform path syntax is reported as a clear retryable save error, while the editor keeps the unsaved buffer intact for another attempt.
 - **Untitled drafts** start as `untitled-*.md` and are auto-renamed on save once the note gains an H1.
 
 ### Title Surface (UI)