fix: refine web chat session selector

CHANGELOG.md

@@ -39,6 +39,7 @@
 ### Fixes
 - Chat UI: keep the chat scrolled to the latest message after switching sessions.
 - Chat UI: add extra top padding before the first message bubble in Web Chat (macOS/iOS/Android).
+- Control UI: refine Web Chat session selector styling (chevron spacing + background).
 - WebChat: stream live updates for sessions even when runs start outside the chat UI.
 - Gateway CLI: read `CLAWDIS_GATEWAY_PASSWORD` from environment in `callGateway()` — allows `doctor`/`health` commands to auth without explicit `--password` flag.
 - Auto-reply: strip stray leading/trailing `HEARTBEAT_OK` from normal replies; drop short (≤ 30 chars) heartbeat acks.

src/canvas-host/a2ui/.bundle.hash

@@ -1 +1 @@
-13cc362f2bc44e2a05a6da5e5ba66ea602755f18ed82b18cf244c8044aa84c36
+988ec7bedb11cab74f82faf4475df758e6f07866b69949ffc2cce89cb3d8265b

ui/src/styles/components.css

@@ -214,6 +214,23 @@
   outline: none;
 }
 
+.field select {
+  appearance: none;
+  padding-right: 38px;
+  background-color: var(--panel-strong);
+  background-image:
+    linear-gradient(45deg, transparent 50%, var(--muted) 50%),
+    linear-gradient(135deg, var(--muted) 50%, transparent 50%),
+    linear-gradient(to right, transparent, transparent);
+  background-position:
+    calc(100% - 18px) 50%,
+    calc(100% - 12px) 50%,
+    calc(100% - 38px) 50%;
+  background-size: 6px 6px, 6px 6px, 1px 60%;
+  background-repeat: no-repeat;
+  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
+}
+
 .field textarea {
   font-family: var(--mono);
   min-height: 180px;