fix: widen instances panel so tool preview + approval buttons don't clip

Active sessions with a tool call preview + inline approval buttons can
render ~130pt tall, but the panel height used perSession=65 + baseHeight=100
which left only ~115pt of ScrollView area after header + bottom padding.
The bottom row ended up under the buddy/stats overlay even though the
ScrollView could technically scroll to it.

Bumps to baseHeight=120 / perSession=100 — gives 1 session 220pt, 2 sessions
320pt, etc. Still capped by expandedMax so large session counts still fit
inside 65% of screen height.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ClaudeIsland/Core/NotchViewModel.swift

@@ -132,8 +132,8 @@ class NotchViewModel: ObservableObject {
                 height: min(screenRect.height * 0.78, 780)
             )
         case .instances:
-            let baseHeight: CGFloat = 100
-            let perSession: CGFloat = 65
+            let baseHeight: CGFloat = 120
+            let perSession: CGFloat = 100
             let contentHeight = baseHeight + CGFloat(sessionCount) * perSession
             // ≤4 sessions: fit content + room for buddy; >4: capped unless expanded
             let compactMax: CGFloat = 360