Close a card by pressing its words, and let a selection be put away

A markdown paragraph took every tap that landed on its glyphs, so an opened
peer message or memory note could be shut anywhere except on the text --
which is most of it, and reads as a card that has stopped working. Measured
on the emulator: with a handler on the text the tap did nothing at all, and
with the handler removed the same tap shut the card. The words now do the
shutting, through a composition local, since the renderer composes those
paragraphs out of its own component table and there is nothing between the
card and them to pass a parameter through. The link handler is bounded by
the long-press timeout, so holding to select is not a tap.

The other half is the tap that puts a selection away, which used to shut
whatever card the words were in. The container clears the selection from
that same press, milliseconds before the card reads it, so the answer is
taken at composition instead -- what was true when the reader touched the
screen.

Selection colours are the app's own. Material's 40% of primary is a tint of
whatever is behind it, and over the near-black a code block sits on it
composited to a smudge, so selecting a line of code looked like nothing had
happened.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/androidApp/src/main/kotlin/com/example/aiapp/Theme.kt

@@ -1,5 +1,6 @@
 package com.example.aiapp
 
+import androidx.compose.foundation.text.selection.TextSelectionColors
 import androidx.compose.material3.ButtonColors
 import androidx.compose.material3.ButtonDefaults
 import androidx.compose.material3.MaterialTheme
@@ -257,6 +258,26 @@ fun ansiPalette(): AnsiPalette =
         background = Mocha.Crust,
     )
 
+/**
+ * What a selection looks like, stated rather than left to Material's default.
+ *
+ * The default is `primary` at 40% alpha, which is a tint of whatever is behind it -- and this app
+ * draws text on surfaces two full steps apart. Over a reply, on Base, that reads clearly. Over a
+ * code block or a tool's output, on Crust, the same 40% composites to a barely-there smudge, so
+ * selecting a line of code looks like nothing happened even though the selection is there and
+ * copies correctly.
+ *
+ * Fixed and stronger, because "this is selected" is a meaning rather than decoration: a colour that
+ * means something must carry its own contrast instead of borrowing it from the surface it happens
+ * to land on. Raised only as far as it takes to read on the darkest of them -- past this the fill
+ * starts competing with the syntax colours it sits behind, which are the thing being read.
+ */
+val AiAppSelectionColors =
+    TextSelectionColors(
+        handleColor = Mocha.Mauve,
+        backgroundColor = Mocha.Mauve.copy(alpha = 0.55f),
+    )
+
 /**
  * A link. Blue is what a link is on every Catppuccin surface, and the one colour to leave alone.
  */