feat(plugins): reach a running agent's composer by reference

useComposers(selector) in any plugin component and composers(selector) on every command context return the composer of a running agent, named by id or by focus, whether or not its tab is open.

A running agent now has one store-backed composer model apart from any mounted tab. The mounted composer plugs its cursor-aware insert in while mounted; otherwise insertText and setPrompt write the agent's saved prompt. model and thinking resolve through the provider catalog with the picker's own function, so a read equals what the picker shows.

The host reads one ComposerModel from context and no longer knows whether it is in an agent, a draft or New workspace. The daemon rejects an unlisted model or thinking option for a running agent, replacing the app-side guard.

plugin-examples/composer-controls/client/controls.tsx

@@ -10,7 +10,7 @@ const CONTEXT_OPTIONS = [
 ] as const;
 
 const CONTEXT_KEY = "composer-controls.contextLength";
-const REVIEW_KEY = "composer-controls.needsReview";
+export const REVIEW_KEY = "composer-controls.needsReview";
 
 /** Reads and writes agent metadata, so the choice is saved with the agent. */
 export function ContextLength() {

plugin-examples/composer-controls/client/panel.tsx

@@ -0,0 +1,56 @@
+import { useCallback, useMemo } from "react";
+import { Pressable, Text, View } from "react-native";
+import { useComposers, type PluginWorkspacePanelProps } from "@getpaseo/plugin/client";
+import { REVIEW_KEY } from "./controls";
+
+/**
+ * Lives in the Explorer, away from any composer, and reaches the composer of the agent whose tab
+ * is focused. The agent's tab does not have to be open for the composer to exist: the text lands in
+ * its prompt either way.
+ */
+export function ComposerTools({ theme, layout }: PluginWorkspacePanelProps) {
+  const [focused] = useComposers({ focused: true });
+  const styles = useMemo(
+    () => ({
+      screen: {
+        flex: 1,
+        padding: layout.compact ? 16 : 24,
+        gap: 12,
+        backgroundColor: theme.colors.surface0,
+      },
+      label: { color: theme.colors.foregroundMuted },
+      button: {
+        padding: 12,
+        borderRadius: 8,
+        backgroundColor: focused ? theme.colors.accent : theme.colors.surface2,
+      },
+      buttonText: {
+        color: focused ? theme.colors.accentForeground : theme.colors.foregroundMuted,
+        textAlign: "center" as const,
+      },
+    }),
+    [focused, layout.compact, theme],
+  );
+  const insert = useCallback(() => focused?.insertText("- [ ] Tests\n- [ ] Docs\n"), [focused]);
+  return (
+    <View style={styles.screen}>
+      <Text style={styles.label}>
+        {focused ? `Focused agent: ${focused.agent.provider}` : "No agent is focused"}
+      </Text>
+      {focused ? (
+        <Text style={styles.label}>
+          {focused.agent.metadata[REVIEW_KEY] === true ? "Needs review: yes" : "Needs review: no"}
+        </Text>
+      ) : null}
+      <Pressable
+        accessibilityRole="button"
+        accessibilityLabel="Insert checklist into the focused agent"
+        disabled={!focused}
+        onPress={insert}
+        style={styles.button}
+      >
+        <Text style={styles.buttonText}>Insert checklist into the focused agent</Text>
+      </Pressable>
+    </View>
+  );
+}