web: deep-link auto-connect + machine-readable connection status (#1576)

Closes #1576

Adds `?serverUrl=<url>&transport=http|sse&autoConnect=<token>` URL-driven
auto-connect so a driver can reach a connected inspector with one navigate.

- `clients/web/src/utils/deepLink.ts`: `parseDeepLink()` (http(s)-only
  serverUrl; `autoConnect` CSRF-gated on the per-launch API token),
  `deepLinkParseStatus()`, `deepLinkConfigEquals()`, `DEEP_LINK_SERVER_ID`
  (stable `deep-link` row so reloads reconnect to the same catalog row).
- App.tsx: ensure/connect effects (two-phase upsert-then-connect against the
  hydrated list), `serversRef` read in `onToggleConnection`,
  `connectErrorMessage` / `recordConnectError` recording connection-level
  failures.
- InspectorView header: `data-testid="connection-status"` with `data-status`,
  `data-error-message`, `data-deeplink` so drivers can `waitForSelector` and
  read failure reasons without scraping toasts.
- Docs: deep-link scheme + `data-*` contract in clients/web/README.md.

Re-implemented informed by PR #1510 (33fac3f); adapted to the post-#1417
lifted-tab architecture and dropping the non-existent `normalizeServerUrl`
import in favor of `URL.href` canonicalization. Coverage gate green
(deepLink.ts 97.8/95.1/100/97.4).

Part of the #1579 decomposition (Wave 4).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BrihGWcrM9JGRyu41nzZYw

clients/web/src/components/views/InspectorView/InspectorView.test.tsx

@@ -259,6 +259,42 @@ describe("InspectorView", () => {
     expect(onToggleConnection).toHaveBeenCalledWith("alpha");
   });
 
+  it("exposes the machine-readable connection-status header attributes for drivers", () => {
+    renderWithMantine(
+      <StatefulInspectorViewHost
+        {...makeProps({
+          servers: [sampleServer],
+          connectionStatus: "error",
+          connectErrorMessage: "handshake failed: 500",
+          deepLinkStatus: "rejected",
+        })}
+      />,
+    );
+    const header = screen.getByTestId("connection-status");
+    expect(header).toHaveAttribute("data-status", "error");
+    expect(header).toHaveAttribute(
+      "data-error-message",
+      "handshake failed: 500",
+    );
+    expect(header).toHaveAttribute("data-deeplink", "rejected");
+  });
+
+  it("omits the error-message attribute when no connect error is recorded", () => {
+    renderWithMantine(
+      <StatefulInspectorViewHost
+        {...makeProps({
+          servers: [sampleServer],
+          connectionStatus: "disconnected",
+          deepLinkStatus: "none",
+        })}
+      />,
+    );
+    const header = screen.getByTestId("connection-status");
+    expect(header).toHaveAttribute("data-status", "disconnected");
+    expect(header).not.toHaveAttribute("data-error-message");
+    expect(header).toHaveAttribute("data-deeplink", "none");
+  });
+
   it("renders the connected header when connectionStatus + initializeResult are set", () => {
     renderWithMantine(
       <StatefulInspectorViewHost

clients/web/src/components/views/InspectorView/InspectorView.tsx

@@ -6,6 +6,7 @@ import {
   type ReactNode,
   type Ref,
 } from "react";
+import type { DeepLink, DeepLinkParseStatus } from "../../../utils/deepLink";
 import {
   AppShell,
   Flex,
@@ -304,6 +305,21 @@ const MonitorColumnGroup = Group.withProps({
 });
 
 export interface InspectorViewProps {
+  /**
+   * Validated deep-link parameters from the page URL. When present and
+   * `openApp` is set, the parent switches to the Apps tab and pre-selects that
+   * app (with `appArgs` as the form values) once the connection is up and the
+   * app list contains it. The connect itself is driven by the parent.
+   */
+  deepLink?: DeepLink;
+  /**
+   * Outcome of parsing the initial-URL deep link, surfaced as `data-deeplink`
+   * on the `connection-status` testid. Distinguishes "no deep link" from
+   * "rejected" (token mismatch / bad serverUrl) — both leave `data-status`
+   * idle, so an automated driver otherwise cannot tell them apart.
+   */
+  deepLinkStatus?: DeepLinkParseStatus;
+
   // Server list (static config; runtime connection state comes from the
   // separate fields below and is merged into each card by this component).
   servers: ServerEntry[];
@@ -324,6 +340,13 @@ export interface InspectorViewProps {
    */
   erroredServerId?: string;
   connectionStatus: ConnectionStatus;
+  /**
+   * Last connection-level error message (handshake failure, OAuth start
+   * failure, deep-link automation failure). Surfaced as `data-error-message`
+   * on the header's `connection-status` testid so an automated driver can read
+   * *why* a connect failed without scraping a transient toast.
+   */
+  connectErrorMessage?: string;
   initializeResult?: InitializeResult;
   latencyMs?: number;
 
@@ -497,11 +520,13 @@ export interface InspectorViewProps {
 }
 
 export function InspectorView({
+  deepLinkStatus,
   servers: serversInput,
   serverListWritable = true,
   activeServer,
   erroredServerId,
   connectionStatus,
+  connectErrorMessage,
   initializeResult,
   latencyMs,
   tools,
@@ -1037,7 +1062,12 @@ export function InspectorView({
     // Main-slot height clamp + overflow:hidden keep that scroll on the inner
     // ScrollArea regions only.
     <AppShell header={{ height: 60 }} padding={0}>
-      <AppShell.Header>
+      <AppShell.Header
+        data-testid="connection-status"
+        data-status={connectionStatus}
+        data-error-message={connectErrorMessage}
+        data-deeplink={deepLinkStatus}
+      >
         {connectionStatus === "connected" && initializeResult ? (
           <ViewHeader
             connected