docs: document code block wrapping and the copy button

Records why the block style carries white-space:pre-wrap and why the
padding is margins plus a spacer line: Qt's markdown stylesheet does not
cover pre, and Qt ignores padding and vertical margins on it. Also
describes the copy button and the constraints behind its shape, since
neither a widget nor :hover is available in Qt rich text.

1 files changed, 20 insertions, 2 deletions

diff --git a/README.md b/README.md
index f53d167..24a5d7f 100644
--- a/README.md
+++ b/README.md
@@ -22,8 +22,10 @@ persistent process and toggles like a scratchpad from a Hyprland keybind.
   words of the question the entry was created with.
 - **Streaming replies** rendered token by token, formatted as markdown:
   headings, bold and italic, bullet and numbered lists, tables, inline code
-  and tinted fenced code blocks. What you type is shown exactly as typed, so
-  the contents of an attached file are never reflowed.
+  and tinted fenced code blocks. Long lines wrap rather than scrolling the
+  transcript sideways, and each code block carries a copy button. What you
+  type is shown exactly as typed, so the contents of an attached file are
+  never reflowed.
 - **Collapsed reasoning.** Presets with a reasoning budget return the model's
   thinking separately from its answer. It shows as a one-line `▸ thinking`
   summary above the reply, and clicking that expands it. Each reply collapses
@@ -563,6 +565,22 @@ handed to the desktop opener.
 
 Qt renders a fenced block as one `<pre>` element per line with no background
 of its own, so llamachat adds the tint that makes a code block read as one.
+Qt also ignores `padding` and vertical margins on `<pre>`, so the inset comes
+from left and right margins and the room above and below from a tinted spacer
+line. Without an explicit `white-space:pre-wrap` a long line would widen the
+whole transcript: Qt's own markdown stylesheet wraps `p` and `li` but not
+`pre`, and that stylesheet is dropped when only the body fragment is kept.
+
+Each code block gets a copy button below it, on the right. Qt rich text has
+no widgets and no `:hover`, so the button is an anchor in the same internal
+scheme dispatch the thinking and search toggles use, and hovering is a
+re-render driven by `QTextBrowser.highlighted()`. It sits below the block
+because Qt cannot float it over the tint. The button is grey at rest, takes
+the highlight colour under the pointer, and becomes a green tick for a moment
+once used; the tick reverts on its own rather than standing indefinitely and
+implying the clipboard still holds that block. The text is copied from the
+source markdown, not the rendered HTML, which per-line `<pre>` elements would
+make unrecoverable.
 
 ## Notes and limits