fix(pi): accept typed connection hooks in pi()

[eersnington]

pi() constrained TUserActions with PiUserActions<...>. TypeScript did not infer the connection state type from createConnState through that constraint, so app actions saw c.conn.state and connection params without their types and needed casts.

Now the actions in the config are typed through an intersection with UserActions<...>, and TUserActions is a plain Record<string, unknown>. The action's c takes its type from the config, so c.conn.state has the type that createConnState returns:

const agent = pi({
	registry: createRegistry(),
	createConnState: async (_c, params: { token: string }) => {
		const user = users.get(params.token);
		if (!user) throw new UserError("Bad token.", { code: "unauthorized" });
		return { userId: user.id };
	},
	actions: {
		// No cast: c.conn.state is { userId: string }.
		whoami: (c): string => c.conn.state.userId,
	},
});

• actor-types.ts: actions?: TUserActions & UserActions<TState, TConnParams, TConnState, ...>.
• actor.ts: TUserActions extends Record<string, unknown> in PiActorConfigInput and pi().
• tests/connection-hooks.test.ts: a bad token is rejected on a built-in call, and a good token connects and the app's action reads c.conn.state.

[railway-app]

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