feat(webapp): move Integrations settings onto the shared settings layout

Rebuilds the project Integrations page with the SettingsContainer,
SettingsSection and SettingsRow primitives already used by the org SSO
page, so GitHub, Vercel and build settings read as one consistent list of
rows instead of headings over bordered boxes.

The page now titles itself "Integrations" rather than inheriting "Project
settings", via a pageTitle handle that the parent settings layout reads.

Also fixes a nested form in the Vercel panel. Browsers drop a nested
<form> when parsing server-rendered HTML, so any project with atomic
production builds and auto-assign custom domains still enabled failed
hydration and re-rendered the whole document on the client.

Carries temporary development-only code (devRevealIntegrations.tsx plus
the devReveal props) that forces every conditionally hidden state to
render at once. That must be removed before this merges.

Author: samejr

apps/webapp/app/assets/icons/PadlockRoundedIcon.tsx

@@ -0,0 +1,34 @@
+export function PadlockRoundedIcon({ className }: { className?: string }) {
+  return (
+    <svg
+      className={className}
+      width="24"
+      height="24"
+      viewBox="0 0 24 24"
+      fill="none"
+      xmlns="http://www.w3.org/2000/svg"
+    >
+      <path
+        d="M5 12C5 10.8954 5.89543 10 7 10H17C18.1046 10 19 10.8954 19 12V19C19 20.1046 18.1046 21 17 21H7C5.89543 21 5 20.1046 5 19V12Z"
+        stroke="currentColor"
+        strokeWidth="2"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+      <path
+        d="M16 9.5V7C16 4.79086 14.2091 3 12 3C9.79086 3 8 4.79086 8 7V9.5"
+        stroke="currentColor"
+        strokeWidth="2"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+      <path
+        d="M12 14V17"
+        stroke="currentColor"
+        strokeWidth="2"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      />
+    </svg>
+  );
+}

apps/webapp/app/components/integrations/devRevealIntegrations.tsx

@@ -0,0 +1,104 @@
+/**
+ * TEMPORARY — DEVELOPMENT ONLY. DELETE THIS FILE BEFORE MERGING.
+ *
+ * The project Integrations settings page hides most of its UI behind
+ * environment config (a configured GitHub App, a configured Vercel
+ * integration) and behind connection state (connected vs. not connected).
+ * Locally that leaves almost nothing on screen, which makes it impossible to
+ * style the page.
+ *
+ * When `DEV_REVEAL_ALL` is true, the page and its two panels render every
+ * state at once using the placeholder data below. Nothing here is wired to a
+ * real integration — the forms still post to their real actions and will fail.
+ *
+ * To revert: set `DEV_REVEAL_ALL` to false, delete this file, and remove every
+ * `devReveal` prop and `DEV_REVEAL_ALL` reference. `rg "DEV_REVEAL_ALL|devReveal"`
+ * finds all of them.
+ */
+
+import { type ReactNode } from "react";
+import { type VercelProjectIntegrationData } from "~/v3/vercel/vercelProjectIntegrationSchema";
+
+export const DEV_REVEAL_ALL = true;
+
+/** Labels a placeholder state so it is obvious it isn't real data. */
+export function DevRevealLabel({ children }: { children: ReactNode }) {
+  if (!DEV_REVEAL_ALL) return null;
+
+  return (
+    <div className="flex items-center gap-2 border-b border-dashed border-amber-500/40 py-2">
+      <span className="rounded-[2px] bg-amber-500/15 px-1.5 py-0.5 font-mono text-[0.625rem] uppercase tracking-wide text-amber-400">
+        dev preview
+      </span>
+      <span className="text-xs text-amber-400/80">{children}</span>
+    </div>
+  );
+}
+
+export const devRevealGitHubInstallations = [
+  {
+    id: "dev-installation",
+    appInstallationId: BigInt(1),
+    targetType: "Organization",
+    accountHandle: "acme-inc",
+    repositories: [
+      {
+        id: "dev-repo",
+        name: "acme-app",
+        fullName: "acme-inc/acme-app",
+        private: true,
+        htmlUrl: "https://github.com/acme-inc/acme-app",
+      },
+    ],
+  },
+];
+
+/** Same repo, but public — so the globe/"This repo is public" state is visible too. */
+export const devRevealConnectedGitHubRepoPublic = {
+  branchTracking: {
+    prod: { branch: "main" },
+    staging: { branch: "staging" },
+  },
+  previewDeploymentsEnabled: true,
+  createdAt: new Date("2026-01-01T00:00:00.000Z"),
+  repository: {
+    ...devRevealGitHubInstallations[0].repositories[0],
+    private: false,
+  },
+};
+
+export const devRevealConnectedGitHubRepo = {
+  branchTracking: {
+    prod: { branch: "main" },
+    staging: { branch: "staging" },
+  },
+  previewDeploymentsEnabled: true,
+  createdAt: new Date("2026-01-01T00:00:00.000Z"),
+  repository: devRevealGitHubInstallations[0].repositories[0],
+};
+
+const devRevealVercelIntegrationData: VercelProjectIntegrationData = {
+  vercelProjectId: "prj_dev",
+  vercelProjectName: "acme-app",
+  vercelTeamId: "team_dev",
+  syncEnvVarsMapping: {},
+  onboardingCompleted: true,
+  config: {
+    atomicBuilds: ["prod"],
+    pullEnvVarsBeforeBuild: ["prod", "preview"],
+    discoverEnvVars: ["prod"],
+    vercelStagingEnvironment: { environmentId: "env_dev", displayName: "staging" },
+    autoPromote: true,
+  },
+};
+
+export const devRevealConnectedVercelProject = {
+  id: "dev-vercel-integration",
+  vercelProjectId: "prj_dev",
+  vercelProjectName: "acme-app",
+  vercelTeamId: "team_dev" as string | null,
+  createdAt: new Date("2026-01-01T00:00:00.000Z"),
+  integrationData: devRevealVercelIntegrationData,
+};
+
+export const devRevealVercelCustomEnvironments = [{ id: "env_dev", slug: "staging" }];