feat: prefill agent-edit modal, Ctrl+Enter submits modals, improve README

- AgentFormModal: sync form state to current agent values when the modal
  opens (useEffect on open/agent), so edit always shows the agent's
  current name, description, website, icon URL, and max-pending value.
- Modal: add optional onSubmit prop; Ctrl+Enter (or ⌘+Enter) fires it,
  covering AgentFormModal, DecisionModal, and both Settings modals
  (disable 2FA, delete account) without breaking textarea newlines or
  text-input behaviour.
- README: substantially expanded — purpose, capabilities, architecture,
  quick-start with Docker Compose, dev setup, testing, agent integration
  (OpenClaw, generic MCP, REST), and privacy notes.
- TODO.md: remove three completed items (prefill modal, Ctrl+Enter, human
  readme).

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

UI/src/components/Modal.tsx

@@ -3,6 +3,7 @@ import { ReactNode, useEffect } from "react";
 export function Modal({
 	open,
 	onClose,
+	onSubmit,
 	title,
 	children,
 	footer,
@@ -10,6 +11,7 @@ export function Modal({
 }: {
 	open: boolean;
 	onClose: () => void;
+	onSubmit?: () => void;
 	title: string;
 	children: ReactNode;
 	footer?: ReactNode;
@@ -19,6 +21,7 @@ export function Modal({
 		if (!open) return;
 		const onKey = (e: KeyboardEvent) => {
 			if (e.key === "Escape") onClose();
+			if (e.key === "Enter" && (e.ctrlKey || e.metaKey) && onSubmit) onSubmit();
 		};
 		window.addEventListener("keydown", onKey);
 		document.body.style.overflow = "hidden";
@@ -26,7 +29,7 @@ export function Modal({
 			window.removeEventListener("keydown", onKey);
 			document.body.style.overflow = "";
 		};
-	}, [open, onClose]);
+	}, [open, onClose, onSubmit]);
 
 	if (!open) return null;