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/Dividers.kt

@@ -21,11 +21,7 @@ import androidx.compose.ui.unit.dp
  * reader scrolling back, both mean "the session no longer has what is above this", and which of the
  * two it was is said by the words and the colour.
  *
- * The rules take [color] too, so the whole divider reads as one mark of one kind rather than a
- * coloured phrase sitting in an unrelated grey line.
- *
- * Written once here rather than styled at each of them, so the two cannot drift into looking like
- * different kinds of thing.
+ * The rules take [color] too, so the whole divider reads as one mark of one kind.
  */
 @Composable
 fun TranscriptDivider(text: String, color: Color, modifier: Modifier = Modifier) {
@@ -44,9 +40,8 @@ fun TranscriptDivider(text: String, color: Color, modifier: Modifier = Modifier)
  * The mark a clear leaves.
  *
  * Red, and no counts: a clear takes the conversation out of what the session is given, and unlike a
- * compaction it summarises nothing and measures nothing, so there is nothing to report but the
- * fact. Everything above stays on screen and stays scrollable -- the reader can see that, which is
- * why this does not say it.
+ * compaction it summarises nothing and measures nothing. Everything above stays on screen and stays
+ * scrollable -- the reader can see that, which is why this does not say it.
  */
 @Composable
 fun ClearedRow(modifier: Modifier = Modifier) {