feat: wire smart text replacements, autocomplete, Writing Tools toggles

Adds TextSubstitutionPolicy/TextCompletionPolicy/WritingToolsPolicy to
MarkdownEditorConfiguration (previously hardcoded AppKit calls with no
config surface). Outline's existing synced smartText preference now
actually drives smart quotes/dashes. Autocomplete and Writing Tools
get new local-only Settings -> Editor toggles (writingToolsBehavior
was already on unconditionally with no way to turn it off).

Outpost/Features/Account/SettingsView.swift

@@ -15,6 +15,8 @@ struct SettingsView: View {
     @Environment(SessionStore.self) private var session
     @AppStorage("outpost.appearance") private var appearance: AppAppearance = .system
     @AppStorage("outpost.splitViewEnabled") private var isSplitViewEnabled = false
+    @AppStorage("outpost.autocompleteEnabled") private var isAutocompleteEnabled = true
+    @AppStorage("outpost.writingToolsEnabled") private var isWritingToolsEnabled = true
     @AppStorage("outpost.commandPaletteEnabled") private var isCommandPaletteEnabled = true
     @AppStorage("outpost.commandPaletteFullWorkspaceSearch") private var isCommandPaletteFullWorkspaceSearch = false
     @AppStorage(CachingOutlineAPIClient.offlineModeDefaultsKey) private var isOfflineModeEnabled = false
@@ -166,6 +168,26 @@ struct SettingsView: View {
 
             Divider().frame(maxWidth: 480)
 
+            VStack(alignment: .leading, spacing: 6) {
+                Toggle("Autocomplete", isOn: $isAutocompleteEnabled)
+                Text("Show inline predictive-text suggestions while typing, same as Notes and TextEdit. Accept with Tab or →.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+            }
+            .frame(maxWidth: 480, alignment: .leading)
+
+            Divider().frame(maxWidth: 480)
+
+            VStack(alignment: .leading, spacing: 6) {
+                Toggle("Writing Tools", isOn: $isWritingToolsEnabled)
+                Text("Proofread, rewrite, summarize, or compose text using system-provided Apple Intelligence tools. Available on supported Macs and macOS versions.")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+            }
+            .frame(maxWidth: 480, alignment: .leading)
+
+            Divider().frame(maxWidth: 480)
+
             VStack(alignment: .leading, spacing: 6) {
                 Toggle("Command Palette", isOn: $isCommandPaletteEnabled)
                 Text("Press ⌘K to quickly jump to a document or collection. Always searches locally on your device — never a network request while typing.")

Outpost/Features/Collections/DocumentReaderView.swift

@@ -17,6 +17,8 @@ struct DocumentReaderView: View {
     /// Local-only Outpost setting (Settings → Editor), not synced to
     /// Outline — see `SettingsView.editorDetail`.
     @AppStorage("outpost.splitViewEnabled") private var isSplitViewEnabled = false
+    @AppStorage("outpost.autocompleteEnabled") private var isAutocompleteEnabled = true
+    @AppStorage("outpost.writingToolsEnabled") private var isWritingToolsEnabled = true
 
     /// Outline's own "Show line numbers" preference (synced, read via
     /// `session.userPreferences`, not `@AppStorage` — this one's the
@@ -32,6 +34,20 @@ struct DocumentReaderView: View {
     private var editorCodeBlockStyle: CodeBlockStyle {
         showCodeBlockLineNumbers ? .init(horizontalIndent: Self.lineNumberGutterWidth) : .default
     }
+    /// Outline's own "Smart text replacements" preference (synced) — smart
+    /// quotes/dashes while typing. Only meaningful on the editable pane.
+    private var editorTextSubstitution: TextSubstitutionPolicy {
+        let enabled = session.userPreferences?.smartText ?? false
+        return .init(quoteSubstitution: enabled, dashSubstitution: enabled)
+    }
+    /// Local-only Outpost settings (Settings → Editor) — not synced to
+    /// Outline, same as Split View above.
+    private var editorTextCompletion: TextCompletionPolicy {
+        .init(isEnabled: isAutocompleteEnabled)
+    }
+    private var editorWritingTools: WritingToolsPolicy {
+        .init(isEnabled: isWritingToolsEnabled)
+    }
 
     @State private var viewModel: DocumentReaderViewModel
     let apiClient: OutlineAPIClient
@@ -337,6 +353,9 @@ struct DocumentReaderView: View {
                             configuration: .init(
                                 services: .init(syntaxHighlighter: CodeSyntaxHighlighting.shared),
                                 codeBlock: editorCodeBlockStyle,
+                                textSubstitution: editorTextSubstitution,
+                                textCompletion: editorTextCompletion,
+                                writingTools: editorWritingTools,
                                 heightBehavior: .fitsContent
                             ),
                             documentId: viewModel.documentId,

Vendor/swift-markdown-engine/Sources/MarkdownEngine/Configuration/MarkdownEditorConfiguration.swift

@@ -48,6 +48,16 @@ public struct MarkdownEditorConfiguration: Sendable {
     /// Centered reading-column width; wide tables break out to full width. nil = full width (default).
     public var readingWidth: CGFloat?
     public var spellChecking: SpellCheckingPolicy
+    /// Smart quote/dash substitution while typing. Independent of `spellChecking`
+    /// — AppKit tracks these as separate `NSTextView` flags.
+    public var textSubstitution: TextSubstitutionPolicy
+    /// Inline predictive-text completion (the ghost-text suggestion AppKit
+    /// shows as you type, same feature as Notes/TextEdit). Mirrors
+    /// `NSTextView.isAutomaticTextCompletionEnabled`.
+    public var textCompletion: TextCompletionPolicy
+    /// System Writing Tools (proofread/rewrite/summarize). Mirrors
+    /// `NSTextView.writingToolsBehavior` — `.none` when disabled.
+    public var writingTools: WritingToolsPolicy
     /// How the editor resolves its own height.
     ///
     /// - `.scrolls` (default): the editor scrolls internally within whatever
@@ -107,6 +117,9 @@ public struct MarkdownEditorConfiguration: Sendable {
         textInsets: TextInsets = .default,
         readingWidth: CGFloat? = nil,
         spellChecking: SpellCheckingPolicy = .default,
+        textSubstitution: TextSubstitutionPolicy = .default,
+        textCompletion: TextCompletionPolicy = .default,
+        writingTools: WritingToolsPolicy = .default,
         heightBehavior: HeightBehavior = .scrolls,
         rawSourceMode: Bool = false,
         extensions: [any MarkdownExtension] = [],
@@ -133,6 +146,9 @@ public struct MarkdownEditorConfiguration: Sendable {
         self.textInsets = textInsets
         self.readingWidth = readingWidth
         self.spellChecking = spellChecking
+        self.textSubstitution = textSubstitution
+        self.textCompletion = textCompletion
+        self.writingTools = writingTools
         self.heightBehavior = heightBehavior
         self.rawSourceMode = rawSourceMode
         self.extensions = extensions
@@ -168,6 +184,59 @@ public struct SpellCheckingPolicy: Sendable {
     public static let `default` = SpellCheckingPolicy()
 }
 
+// MARK: - Text substitution
+
+/// Smart quote/dash substitution while typing. Mirrors the historical
+/// hardcoded `NativeTextViewWrapper` behavior (quotes on, dashes off) as the
+/// default, now exposed as a config knob instead of fixed AppKit calls.
+public struct TextSubstitutionPolicy: Sendable {
+    /// Mirrors `NSTextView.isAutomaticQuoteSubstitutionEnabled`.
+    public var quoteSubstitution: Bool
+    /// Mirrors `NSTextView.isAutomaticDashSubstitutionEnabled`.
+    public var dashSubstitution: Bool
+
+    public init(
+        quoteSubstitution: Bool = true,
+        dashSubstitution: Bool = false
+    ) {
+        self.quoteSubstitution = quoteSubstitution
+        self.dashSubstitution = dashSubstitution
+    }
+
+    public static let `default` = TextSubstitutionPolicy()
+}
+
+// MARK: - Text completion
+
+/// Inline predictive-text completion while typing (ghost-text suggestion,
+/// accepted with Tab/→ — same feature as Notes/TextEdit on macOS 14+).
+public struct TextCompletionPolicy: Sendable {
+    /// Mirrors `NSTextView.isAutomaticTextCompletionEnabled`.
+    public var isEnabled: Bool
+
+    public init(isEnabled: Bool = true) {
+        self.isEnabled = isEnabled
+    }
+
+    public static let `default` = TextCompletionPolicy()
+}
+
+// MARK: - Writing Tools
+
+/// System Writing Tools (proofread / rewrite / summarize / compose), backed
+/// by Apple Intelligence where available.
+public struct WritingToolsPolicy: Sendable {
+    /// When `false`, `NSTextView.writingToolsBehavior` is set to `.none`
+    /// instead of `.limited` — hides Writing Tools entirely for this view.
+    public var isEnabled: Bool
+
+    public init(isEnabled: Bool = true) {
+        self.isEnabled = isEnabled
+    }
+
+    public static let `default` = WritingToolsPolicy()
+}
+
 // MARK: - Scroll bars
 
 /// Scroll bar visibility. Default: vertical only, autohide on.

Vendor/swift-markdown-engine/Sources/MarkdownEngine/TextView/Coordinator/NativeTextViewCoordinator+Autocorrect.swift

@@ -62,8 +62,12 @@ extension NativeTextViewCoordinator {
         textView.isGrammarCheckingEnabled = shouldDisableSpelling
             ? false
             : userPrefersGrammarChecking
-        textView.isAutomaticQuoteSubstitutionEnabled = !shouldDisableSpelling
+        textView.isAutomaticQuoteSubstitutionEnabled = shouldDisableSpelling
-        textView.isAutomaticDashSubstitutionEnabled = false
+            ? false
+            : configuration.textSubstitution.quoteSubstitution
+        textView.isAutomaticDashSubstitutionEnabled = shouldDisableSpelling
+            ? false
+            : configuration.textSubstitution.dashSubstitution
     }
 
     func isInsideCode(range: NSRange, in text: String) -> Bool {

Vendor/swift-markdown-engine/Sources/MarkdownEngine/TextView/NativeTextViewWrapper.swift

@@ -280,16 +280,17 @@ public struct NativeTextViewWrapper: NSViewRepresentable {
         textView.isAutomaticSpellingCorrectionEnabled = configuration.spellChecking.automaticSpellingCorrection
         textView.isContinuousSpellCheckingEnabled = configuration.spellChecking.continuousSpellChecking
         textView.isGrammarCheckingEnabled = configuration.spellChecking.grammarChecking
-        textView.isAutomaticQuoteSubstitutionEnabled = true
+        textView.isAutomaticQuoteSubstitutionEnabled = configuration.textSubstitution.quoteSubstitution
         textView.isAutomaticDataDetectionEnabled = true
-        textView.isAutomaticDashSubstitutionEnabled = false
+        textView.isAutomaticDashSubstitutionEnabled = configuration.textSubstitution.dashSubstitution
         textView.onPasteImage = onPasteImage
+        textView.isAutomaticTextCompletionEnabled = configuration.textCompletion.isEnabled
         if #available(macOS 15.1, *) {
             // `.limited` = the Writing Tools popover panel; `.complete` = the inline
             // experience that morphs the text with an animation. We use `.limited` so
             // rewrites/proofread land in the popover (no in-text animation) — it also
             // sidesteps the inline-rewrite flicker that dims text below the selection.
-            textView.writingToolsBehavior = .limited
+            textView.writingToolsBehavior = configuration.writingTools.isEnabled ? .limited : .none
         }
         // Create TextKit 2 layout bridge
         let bridge = LayoutBridge(textLayoutManager)