feat: show sharing info at bottom of AppLink's tooltip (#21197)

for #19974 

`ShareIcon`, which returns a MUI tooltip, had these problems:

1. There was no Storybook story which rendered the "Open external URL"
tooltip
2. `AppLink` renders a button. If it has tooltip text, this button is
also a Radix `TooltipTrigger`. Since `ShareIcon` is rendered as a child
of the `AppLink` button, `ShareIcon`'s tooltip (a nested tooltip) was
never appearing. I did try turning `ShareIcon` into a Radix tooltip as
well, but I still couldn't get the nested tooltip's text to appear, and
nested tooltips are not very accessible. AFAIK there's no way to focus a
child element of a button.

I've deleted the separate `ShareIcon` component and moved `ShareIcon`'s
tooltip text to the bottom of `AppLink`'s tooltip:

## before

<img width="175" height="121" alt="image"
src="https://github.com/user-attachments/assets/ad17927e-c3d1-499b-83f8-a5832b777305"
/>

^The `UsersIcon` on the right is a MUI tooltip trigger, but it can't
receive focus. It's supposed to show the text "Shared with all
authenticated users" when focused

## after

<img width="228" height="121" alt="image"
src="https://github.com/user-attachments/assets/adc202c1-57cd-4a80-8f94-f7f32897d286"
/>

site/src/modules/resources/AppLink/AppLink.stories.tsx

@@ -77,6 +77,19 @@ export const ExternalAppNotInstalled: Story = {
 	},
 };
 
+export const ExternalAppShareable: Story = {
+	args: {
+		workspace: MockWorkspace,
+		app: {
+			...MockWorkspaceApp,
+			url: "vscode://open",
+			external: true,
+			sharing_level: "authenticated",
+		},
+		agent: MockWorkspaceAgent,
+	},
+};
+
 export const SharingLevelOwner: Story = {
 	args: {
 		workspace: MockWorkspace,

site/src/modules/resources/AppLink/AppLink.tsx

@@ -9,13 +9,19 @@ import {
 	TooltipTrigger,
 } from "components/Tooltip/Tooltip";
 import { useProxy } from "contexts/ProxyContext";
-import { CircleAlertIcon } from "lucide-react";
+import {
+	Building2Icon,
+	CircleAlertIcon,
+	GlobeIcon,
+	type LucideIcon,
+	SquareArrowOutUpRightIcon,
+	UsersIcon,
+} from "lucide-react";
 import { isExternalApp, needsSessionToken } from "modules/apps/apps";
 import { useAppLink } from "modules/apps/useAppLink";
 import { type FC, type ReactNode, useState } from "react";
 import { AgentButton } from "../AgentButton";
 import { BaseIcon } from "./BaseIcon";
-import { ShareIcon } from "./ShareIcon";
 
 export const DisplayAppNameMap: Record<TypesGen.DisplayApp, string> = {
 	port_forwarding_helper: "Ports",
@@ -115,13 +121,24 @@ export const AppLink: FC<AppLinkProps> = ({
 	}
 
 	const canShare = app.sharing_level !== "owner";
+	const { shareTooltip, shareIcon: ShareIcon } = canShare
+		? app.external
+			? {
+					shareTooltip: "Open external URL",
+					shareIcon: SquareArrowOutUpRightIcon,
+				}
+			: shareDetails[app.sharing_level]
+		: {
+				shareTooltip: null,
+				shareIcon: null,
+			};
 
 	const button = grouped ? (
 		<DropdownMenuItem asChild>
 			<a href={canClick ? link.href : undefined} onClick={link.onClick}>
 				{icon}
 				{link.label}
-				{canShare && <ShareIcon app={app} />}
+				{ShareIcon && <ShareIcon />}
 			</a>
 		</DropdownMenuItem>
 	) : (
@@ -129,7 +146,7 @@ export const AppLink: FC<AppLinkProps> = ({
 			<a href={canClick ? link.href : undefined} onClick={link.onClick}>
 				{icon}
 				{link.label}
-				{canShare && <ShareIcon app={app} />}
+				{ShareIcon && <ShareIcon />}
 			</a>
 		</AgentButton>
 	);
@@ -146,6 +163,7 @@ export const AppLink: FC<AppLinkProps> = ({
 							{app.tooltip}
 						</Markdown>
 					) : null}
+					{shareTooltip}
 				</TooltipContent>
 			</Tooltip>
 		);
@@ -153,3 +171,23 @@ export const AppLink: FC<AppLinkProps> = ({
 
 	return button;
 };
+
+const shareDetails: {
+	[SharingLevel in TypesGen.WorkspaceAppSharingLevel as Exclude<
+		SharingLevel,
+		"owner"
+	>]: { shareTooltip: string; shareIcon: LucideIcon };
+} = {
+	authenticated: {
+		shareTooltip: "Shared with all authenticated users",
+		shareIcon: UsersIcon,
+	},
+	organization: {
+		shareTooltip: "Shared with organization members",
+		shareIcon: Building2Icon,
+	},
+	public: {
+		shareTooltip: "Shared publicly",
+		shareIcon: GlobeIcon,
+	},
+};

site/src/modules/resources/AppLink/ShareIcon.tsx

@@ -1,45 +0,0 @@
-import Tooltip from "@mui/material/Tooltip";
-import type * as TypesGen from "api/typesGenerated";
-import {
-	Building2Icon,
-	GlobeIcon,
-	SquareArrowOutUpRightIcon,
-	UsersIcon,
-} from "lucide-react";
-
-interface ShareIconProps {
-	app: TypesGen.WorkspaceApp;
-}
-
-export const ShareIcon = ({ app }: ShareIconProps) => {
-	if (app.external) {
-		return (
-			<Tooltip title="Open external URL">
-				<SquareArrowOutUpRightIcon />
-			</Tooltip>
-		);
-	}
-	if (app.sharing_level === "authenticated") {
-		return (
-			<Tooltip title="Shared with all authenticated users">
-				<UsersIcon />
-			</Tooltip>
-		);
-	}
-	if (app.sharing_level === "organization") {
-		return (
-			<Tooltip title="Shared with organization members">
-				<Building2Icon />
-			</Tooltip>
-		);
-	}
-	if (app.sharing_level === "public") {
-		return (
-			<Tooltip title="Shared publicly">
-				<GlobeIcon />
-			</Tooltip>
-		);
-	}
-
-	return null;
-};