M4.57: PNG, PDF and text clipboard flavours in and out

Copy and Cut also offer other apps a PNG of the copied objects, a PDF
with On Copy: PDF, and plain text when every copied object is type
(clipboard.flavours; clipboard.exportPng {scale?}, exportPdf,
exportText). Paste outside text editing takes what another app copied:
SVG, then PDF (clipboard.importPdf), then plain text as point text
(clipboard.importText), then a bitmap embedded at the view centre
(clipboard.importImage {dataBase64, mime?, center?}); pasting our own
copy keeps the lossless internal clipboard, and Cmd+V pastes a bitmap
that comes with no text. Services gains system_clipboard
(SystemClipboard: write, holds_ours, read, has): on Windows every
format at once, on macOS and Linux one (the text, else the PNG); the
web keeps SVG text only. With When pasting text: Keep Plain Text, text
the Type tool copied pastes without its formatting.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/tools/src/lib.rs

@@ -206,6 +206,9 @@ pub struct ToolContext<'a> {
     pub unit: Unit,
     /// Units ▸ Stroke: the unit measurement labels show stroke widths in.
     pub stroke_unit: Unit,
+    /// Clipboard Handling → When pasting text: Keep Plain Text. Text pasted while typing takes
+    /// the style at the caret, even the text the Type tool copied with its formatting.
+    pub paste_plain_text: bool,
 }
 
 impl ToolContext<'_> {
@@ -405,6 +408,7 @@ pub(crate) mod testutil {
             preview_bounds: false,
             unit: Unit::Points,
             stroke_unit: Unit::Points,
+            paste_plain_text: false,
         }
     }
 }

crates/tools/src/text.rs

@@ -365,9 +365,9 @@ impl Tool for TypeTool {
             s
         };
         self.clicks = (None, 0);
-        // Pasting what we copied keeps its formatting.
+        // Pasting what we copied keeps its formatting (unless pasted text is kept plain).
         let clip: String = self.clipboard.iter().map(|r| r.text.as_str()).collect();
-        if s.len() > 1 && s == clip {
+        if s.len() > 1 && s == clip && !cx.paste_plain_text {
             let runs = self.clipboard.clone();
             return self.replace(cx, "", Some(runs));
         }