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/Drafts.kt

@@ -10,12 +10,11 @@ private const val DRAFTS = "session-drafts"
  *
  * On this device rather than on the backend, which is where this app otherwise keeps state so that
  * every device sees it. A draft is the case that rule is not about: it is the contents of a text
- * box on the phone somebody is holding, written on every keystroke, and half a sentence surfacing
- * on another device would be a surprise rather than a convenience. What has been *sent* is the
- * server's, and that is the part which has to outlive this phone.
+ * box on the phone somebody is holding, and half a sentence surfacing on another device would be a
+ * surprise. What has been *sent* is the server's.
  *
- * Kept per session id, because the thing being typed belongs to the conversation it is aimed at:
- * one shared box would hand a message meant for one session to whichever was opened next.
+ * Kept per session id: one shared box would hand a message meant for one session to whichever was
+ * opened next.
  */
 fun loadDraft(context: Context, sessionId: String): String =
     context.getSharedPreferences(DRAFTS, Context.MODE_PRIVATE).getString(sessionId, "").orEmpty()
@@ -23,11 +22,9 @@ fun loadDraft(context: Context, sessionId: String): String =
 /**
  * Records [text] as the draft for [sessionId], or forgets it when there is nothing left to keep.
  *
- * The path out is emptying the box, which is what sending does -- so a sent message removes its own
- * entry and nothing accumulates for a session in ordinary use. A session *deleted* while it held a
- * draft does leave its key behind: pruning those means a pass over the live session list, which
- * this file would otherwise have no reason to know about, and the residue is a few bytes per
- * session ever abandoned mid-sentence. That is a trade rather than an oversight.
+ * The path out is emptying the box, which is what sending does. A session *deleted* while it held a
+ * draft does leave its key behind: pruning those means a pass over the live session list, and the
+ * residue is a few bytes per session ever abandoned mid-sentence.
  */
 fun saveDraft(context: Context, sessionId: String, text: String) {
     context.getSharedPreferences(DRAFTS, Context.MODE_PRIVATE).edit {