[chore] bump AGP 9.0.1 → 9.1.1 — fix R8 kotlin metadata warnings (#900)

* chore(build): bump AGP 9.0.1 → 9.1.1 — fix R8 kotlin metadata warnings

Kotlin 2.4.10 emits metadata the R8 bundled in AGP 9.0.1 cannot parse:
'WARNING: R8: An error occurred when parsing kotlin metadata' spam on every
release build (the Kotlin↔R8 compatibility matrix requires R8 ≥ 9.1.29 for
Kotlin 2.4). AGP 9.1.1 bundles R8 9.1.x — release build now warning-free.

Verified locally: assembleRelease green with zero metadata warnings; unit
suite 1029/0; device smoke — app connects with preserved token under R8 9.1.

* fix(chat): removeLast() → removeAt(lastIndex) — API 35 call on minSdk 26

AGP 9.1's lint (newer NewApi check) flags java.util.List#removeLast(),
resolved only as a Kotlin stdlib extension below API 35. Same semantics,
lint-clean.

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/components/MessageCards.kt

@@ -384,7 +384,7 @@ internal fun highlightSyntax(code: String): AnnotatedString =
                 } else if (m.first.first > last.first.first) {
                     // Overlap, this match starts later — it wins the overlapping portion
                     // Keep the last match's pre-overlap, then replace
-                    resolved.removeLast()
+                    resolved.removeAt(resolved.lastIndex)
                     // Split: keep text before overlap from last match
                     if (last.first.first < m.first.first) {
                         resolved.add(last.first.first..<m.first.first to last.second)