[MotherSphere]

What changed

Most editor preferences in the Settings window were stored in the project but never read, and settings reached the disk only when the Settings window closed. Each preference now either works or is gone, and every change is saved at once.

Every project setting and its fate

Field	Fate
editor_font	Wired: sets the editor font. "monospace" keeps the bundled JetBrains Mono, "serif" and "sans-serif" use the system families. Applies to the main editor, the split view, focus mode and composition mode.
editor_font_size	Wired: editor text size.
editor_zoom	Wired: multiplies the text size.
line_spacing	Wired: editor line height, as a multiple of the size.
editor_width	Wired: width of the text column in the main editor, in percent of the panel.
fullscreen_text_width	Wired: width of the text column in composition mode, in percent of the window.
show_word_count	Wired: shows or hides the counts in the status bar.
show_synopsis_in_binder	Wired: a binder item with a synopsis shows it in a tooltip on hover. The control moves to a "Binder" section.
smart_punctuation	Wired: master switch for as-you-type smart punctuation.
auto_correction (new)	The curly quote, em dash and ellipsis toggles were app state that reset on every launch and did nothing. They are now a project setting with three fields (smart_quotes, em_dashes, ellipsis), saved like the others, and applied as you type. Double hyphens at the start of a line, after punctuation or after the | of a table row stay as they are, so Markdown rules (---), comments (<!--) and table rules (|---|, | --- |) keep working.
capitalize_sentences, superscript_ordinals (inside the old auto-correction state)	Deleted: they had no control and nothing read them, so they are not saved in project.json.
auto_save_seconds, target_word_count, target_deadline, auto_backup, backup_interval_saves, labels, statuses	Already read; unchanged.
typewriter_scroll	Deleted with its control: iced's text editor gives no control over its scroll position.
show_paragraph_marks	Deleted with its control: iced's text editor can only colour text, not draw marks that are not in it.
spell_check_enabled	Deleted with its control: there is no as-you-type spell checker, and iced's editor cannot underline. The F7 spell check is unchanged and the Corrections tab now points to it.
default_doc_type	Deleted with its control: binder items have no document type for it to set.
auto_numbering	Deleted with its control: the compiler has no scene numbering.
fullscreen_bg_color, composition_bg_color	Deleted: they had no control and nothing read them.
high_contrast, large_ui, ui_scale, reduce_motion, screen_reader_hints	Untouched here: the shared colony-ui preferences replace them in a follow-up. They are still saved when changed.

Smart punctuation is on by default

smart_punctuation and the three substitutions default to on, and projects saved by older versions already carry smart_punctuation: true, so every existing project now gets curly quotes, em dashes and ellipses as you type. A Backspace right after a correction puts back the characters you typed (", ', --, ...), so a literal straight quote or double hyphen takes one extra key. The README says so.

Saving

• Every message that changes a setting (title, targets, autosave, appearance, corrections, backup, accessibility) saves right away; closing the Settings window no longer has to.
• The save writes only the title and settings into the existing project.json, through the same atomic write as a full save. It does not rewrite every document on each keystroke in a settings field, and it never records binder entries whose documents are not on disk yet. A project that was never saved keeps its settings until its first save, as before.
• Project files written by older versions load unchanged: removed fields are ignored and new ones take their defaults, including each field of auto_correction.

Also in this PR

• Recording an insertion for revision marks sliced the text with a cursor that is not tracked while typing, which panicked when the range fell inside a multi-byte character (a document starting with an accented letter or a curly quote). It now skips the text instead of crashing.
• From fix: start normally when a command-line argument is not valid UTF-8 #18: the --version check reads the command line with std::env::args_os(), so an argument that is not valid UTF-8 no longer aborts Avalon at startup. (fix: start normally when a command-line argument is not valid UTF-8 #18 also replaced an em dash in a Cargo.toml comment; chore(deps): move PDF export to printpdf 0.12 and drop unused dependencies #19 already made that change on main.)
• README: the feature list, the "Projects and files" section and the privacy table describe the saved settings.

How it was verified

• New tests: each wired field changes what it claims (text look, column width, status bar counts, synopsis tooltip, as-you-type corrections through the editor and their toggles, spaced table rules left alone, Backspace right after a correction restoring the typed characters and only then); a settings change is on disk while the window stays open; save_settings leaves unsaved binder entries out; a project.json with every removed field and no auto_correction still loads.
• cargo fmt --check and cargo clippy --locked --all-targets -- -D warnings pass locally, as do the targeted tests. CI runs the full matrix.

BEGIN_COMMIT_OVERRIDE
fix: make every editor preference take effect and save it as soon as it changes
fix: start normally when a command-line argument is not valid UTF-8
END_COMMIT_OVERRIDE