WIP: Major cleanup - move Attachment to consumers, simplify agent API

- Removed Attachment from agent package (now in web-ui/coding-agent)
- Agent.prompt now takes (text, images?: ImageContent[])
- Removed transports from web-ui (duplicate of agent package)
- Updated coding-agent to use local message types
- Updated mom package for new agent API

Remaining: Fix AgentInterface.ts to compose UserMessageWithAttachments

packages/web-ui/src/components/message-renderer-registry.ts

@@ -1,11 +1,11 @@
+import type { AgentMessage } from "@mariozechner/pi-agent-core";
 import type { TemplateResult } from "lit";
-import type { AppMessage } from "./Messages.js";
 
 // Extract role type from AppMessage union
-export type MessageRole = AppMessage["role"];
+export type MessageRole = AgentMessage["role"];
 
 // Generic message renderer typed to specific message type
-export interface MessageRenderer<TMessage extends AppMessage = AppMessage> {
+export interface MessageRenderer<TMessage extends AgentMessage = AgentMessage> {
 	render(message: TMessage): TemplateResult;
 }
 
@@ -14,7 +14,7 @@ const messageRenderers = new Map<MessageRole, MessageRenderer<any>>();
 
 export function registerMessageRenderer<TRole extends MessageRole>(
 	role: TRole,
-	renderer: MessageRenderer<Extract<AppMessage, { role: TRole }>>,
+	renderer: MessageRenderer<Extract<AgentMessage, { role: TRole }>>,
 ): void {
 	messageRenderers.set(role, renderer);
 }
@@ -23,6 +23,6 @@ export function getMessageRenderer(role: MessageRole): MessageRenderer | undefin
 	return messageRenderers.get(role);
 }
 
-export function renderMessage(message: AppMessage): TemplateResult | undefined {
+export function renderMessage(message: AgentMessage): TemplateResult | undefined {
 	return messageRenderers.get(message.role)?.render(message);
 }