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/ResetCountdown.kt

@@ -4,17 +4,16 @@ import java.time.Duration
 import java.time.OffsetDateTime
 
 // How long is left in a usage window. Shared by the session bar and the usage screen: the
-// arithmetic is the same in both and only the sentence around it differs, so everything here
-// returns the span or the state on its own and leaves the wording to the caller.
+// arithmetic is the same in both, so everything here returns the span or the state on its own and
+// leaves the wording to the caller.
 
 /**
  * "1d 4h", "3h 12m", "12m" -- the span alone, with no leading or trailing words.
  *
  * Rounded **up** to the whole minute, rather than truncated as it was. A window with 3h 12m 50s
  * left is nearer four minutes past the twelve than it is to twelve, and truncating also parks the
- * figure on a minute it has already spent -- so the reader watching the number decide whether to
- * start something was consistently told less headroom than they had. One rule, so the session bar
- * and the usage dialog cannot round a shared measurement two different ways.
+ * figure on a minute it has already spent. One rule, so the session bar and the usage dialog cannot
+ * round a shared measurement two different ways.
  */
 fun formatSpan(until: Duration): String {
     val up = if (until.seconds % 60 == 0L && until.nano == 0) until else until.plusMinutes(1)
@@ -31,14 +30,12 @@ fun formatSpan(until: Duration): String {
  * Three answers rather than a nullable duration, because two of them shared `null` and they are not
  * the same thing at all. A window the server sent no reset time for is one that is **not running**:
  * the five-hour window is anchored to the block it started in, so between sessions there is nothing
- * counting down and the API says so by omitting the field -- measured against a live response on
- * 2026-08-31, where the five-hour window's reset was exactly five hours after the moment work
- * resumed. A timestamp that did arrive and could not be read is the genuinely unknown case, and it
- * is the only one worth those words.
+ * counting down and the API says so by omitting the field. A timestamp that did arrive and could
+ * not be read is the genuinely unknown case.
  *
  * Collapsing them put "reset time unknown" on the session bar for a machine behaving perfectly, on
  * the one row somebody reads before starting something big -- and the usage dialog, looking at the
- * same field, quietly drew nothing. Two rules for one missing value; this is the rule.
+ * same field, quietly drew nothing.
  */
 sealed class WindowEnd {
     /** No reset time was sent, so nothing is running in this window. Not a failure to find out. */