agent ui: terminal-themed live panel; pretty tool calls; collapsed results

- tool_use renders per-tool (Read /path, Bash $ cmd, send → operator: ...)
- tool_result with >120 chars collapses into <details>; short ones inline
- session_init / result / rate_limit dropped from the panel
- thinking content shown inline if present, fallback indicator otherwise
- TurnStart carries unread count → header badge "· 3 unread"
- per-tool [status] line dropped from envelope; lives in wake prompt + UI
- send form moved below the live panel
- live panel themed as a terminal (crust bg, inset shadow, monospace)

hive-ag3nt/src/events.rs

@@ -20,7 +20,13 @@ const CHANNEL_CAPACITY: usize = 256;
 #[serde(tag = "kind", rename_all = "snake_case")]
 pub enum LiveEvent {
     /// Harness popped a wake-up message and is about to invoke claude.
-    TurnStart { from: String, body: String },
+    /// `unread` is the count of *other* messages still in the inbox at
+    /// that moment — surfaced as a badge in the live panel header.
+    TurnStart {
+        from: String,
+        body: String,
+        unread: u64,
+    },
     /// One line of claude's `--output-format stream-json` stdout, parsed as
     /// a generic JSON value (so we don't have to track every claude-code
     /// event variant). The frontend pretty-prints by `type` field.