Thin the app's comments

The same pass the server had, on the Kotlin side: comments restating what
the code says are gone, and the ones recording a measurement, a constraint
or an incident are kept but cut to a few lines each. 6540 comment lines to
5674, and 920 lines off the app.

Two doc comments had drifted onto the item above the one they describe --
`contextAfter`'s onto `sessionWorking` in Events.kt, and `UsageMonitor`'s
equivalent on the server was fixed in the previous commit. Each is back on
its own item, which is the only non-comment line this diff moves.

The comments are reflowed to the column limit at their own indentation:
several were written wide, and ktfmt re-wrapped them into lines holding a
single orphan word. `/tmp` script, not kept -- ktfmt is idempotent over the
result, which is the check.

Left alone deliberately: this codebase's remaining comment density is high
because the comments carry things the code cannot say -- what a null means,
what a number was measured against, which bug a guard exists for. Of the
238 one-line doc comments in the app, five were pure restatement of the
name and were removed; the rest each say something the signature does not.

ktfmtFormat, compileDebugKotlin, lintDebug and testDebugUnitTest pass;
cargo test (127), clippy --all-targets and fmt still clean.

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

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

@@ -47,12 +47,11 @@ data class SyntaxPalette(
 /**
  * [code] with its keywords, strings and comments coloured, or plain if there is no language for it.
  *
- * Shared by a tool call's input ([ToolInputView]) and a reply's fences ([CodeFence]), so the same
- * code is the same colours wherever it appears.
+ * Shared by a tool call's input and a reply's fences, so the same code is the same colours wherever
+ * it appears.
  *
  * Not a composable, and it takes no colour from the theme, because that is what lets [warm] run it
- * off the drawing thread: the syntax palette is fixed, and a fence with no language is plain text
- * which needs no colour of its own -- the style the caller draws it with carries that.
+ * off the drawing thread.
  *
  * The timing is the number the highlighter is judged by: the library this replaced took **174ms**
  * on the emulator for a two-hundred-line Kotlin fence, which is why [ParsedReplies.highlighted]
@@ -82,8 +81,7 @@ fun highlight(code: String, language: Language?): AnnotatedString {
  * to the end of the code, which is also what it looks like while a fence is still being written.
  *
  * In ordinary code the order of recognition is comment, string, attribute, number, word, and
- * finally a single punctuation or mark character. Punctuation and marks are coloured only in
- * ordinary code, never inside a string or a comment.
+ * finally a single punctuation or mark character, which are coloured only in ordinary code.
  */
 fun scan(code: String, rules: Rules): List<Span> = Scanner(code, rules).run()
 
@@ -156,8 +154,8 @@ private class Scanner(private val code: String, private val rules: Rules) {
         at += comment.open.length
         var depth = 1
         while (at < code.length && depth > 0) {
-            // The closer is tried first so that a language whose two delimiters are the same
-            // string -- CoffeeScript's `###` -- closes rather than nesting forever.
+            // The closer is tried first so that a language whose two delimiters are the same string
+            // -- CoffeeScript's `###` -- closes rather than nesting forever.
             if (starts(comment.close)) {
                 depth--
                 at += comment.close.length