Fix CLI subagent task routing, Ctrl+C cancellation, and session restore reliability

- Construct ServerTask directly for Bedrock CLI subagents so messages route
  correctly without needing a server CreateTask upgrade
- Handle CliAgentUserQuery input type in both request translators, including
  running command context and terminal output
- Add force_cancel_all_streaming_exchanges fallback for when Ctrl+C finds no
  in-flight streams (stuck subagent / unexpected stream end)
- Cancel active conversation on Ctrl+C in agent view compose state
- Skip agent view entry when agent is tagged-in for a running command
- Set root_task_id on Bedrock requests for proper optimistic task upgrade
- Persist app state on will_terminate to avoid losing sessions
- Trust persisted CWD without is_dir() recheck (fixes network mount restore)
- Log warning instead of silently dropping tabs with unreadable root nodes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/persistence/sqlite.rs

@@ -2755,7 +2755,17 @@ fn read_sqlite_data(
             let saved_tabs: Vec<_> = tabs_for_window
                 .into_iter()
                 .filter_map(|tab| {
-                    let root = read_root_node(conn, tab.id).ok()?;
+                    let root = match read_root_node(conn, tab.id) {
+                        Ok(node) => node,
+                        Err(err) => {
+                            log::warn!(
+                                "[session-restore] Failed to read root node for tab {}: {err}. \
+                                 This tab will not be restored.",
+                                tab.id,
+                            );
+                            return None;
+                        }
+                    };
                     let panel = db_panels.get(&tab.id);
 
                     let left_panel = panel