Say Not supported only for a Mac model the installer refuses

Sources/OmarchyAppleInstallerApp/OnePage/OnePageInstallerView.swift

@@ -151,10 +151,10 @@ struct OnePageInstallerView: View {
           .font(OmarchyTheme.eyebrow)
           .textCase(.uppercase)
           .foregroundStyle(OmarchyTheme.accent)
-        if isBlocked {
-          StatusBadge(text: PlainLanguage.blockedBadge, kind: .blocked)
-        } else {
-          StatusBadge(text: PlainLanguage.supportedBadge, kind: .ok)
+        if let supported = session.modelSupported {
+          StatusBadge(
+            text: supported ? PlainLanguage.supportedBadge : PlainLanguage.blockedBadge,
+            kind: supported ? .ok : .blocked)
         }
         if let channel {
           StatusBadge(text: PlainLanguage.badge(for: channel), kind: .ok)
@@ -169,15 +169,6 @@ struct OnePageInstallerView: View {
     }
   }
 
-  private var isBlocked: Bool {
-    switch session.phase {
-    case .unsupported, .existingInstallRefused:
-      return true
-    default:
-      return false
-    }
-  }
-
   // MARK: The middle of the page
 
   @ViewBuilder

Sources/OmarchyInstallerUXCore/InstallerSession.swift

@@ -136,6 +136,23 @@
       return environment.installationBlocked
     }
 
+    /// The header's word on this Mac model: false only for a refused model, so
+    /// an existing install or too little space never reads as Not supported.
+    /// Nil when the installer stopped before it could tell.
+    public var modelSupported: Bool? {
+      switch phase {
+      case .inspecting:
+        return nil
+      case .existingInstallRefused(let host):
+        return host.supported ? true : nil
+      case .unsupported(let failure):
+        if failure.isBlockedModel { return false }
+        return failure.device?.supported == true ? true : nil
+      default:
+        return true
+      }
+    }
+
     public var credentialSheet: CredentialSheetState {
       if case .awaitingInstall(_, _, let sheet) = phase {
         return sheet

Tests/OmarchyInstallerUXCoreTests/InstallerSessionTests.swift

@@ -1240,6 +1240,63 @@
       XCTAssertEqual(environment.prepareCount, 1)
     }
 
+    /// On the M2 Max (apple,j414c, enabled in the signed catalog) the header
+    /// said NOT SUPPORTED because an older install was still on the disk. Only
+    /// a refused model says that; a stop for any other reason says Supported
+    /// when the Mac is, and nothing when the installer couldn't tell.
+    func testHeaderSaysNotSupportedOnlyForARefusedModel() async {
+      let supported = MockInstallerEnvironment.supportedHost
+      let install = ExistingInstallDisplay(sourceIdentifier: "disk0s3", sizeDescription: "256 GB")
+      let cases: [(String, HostDisplay, Bool, Bool?)] = [
+        ("ready", supported, false, true),
+        (
+          "existing install on a supported Mac",
+          HostDisplay(
+            chipAndSpace: supported.chipAndSpace, supported: true, existingInstalls: [install]),
+          false, true
+        ),
+        (
+          "existing install, engine couldn't tell",
+          HostDisplay(
+            chipAndSpace: supported.chipAndSpace, supported: false, existingInstalls: [install]),
+          false, nil
+        ),
+        (
+          "too little space",
+          HostDisplay(
+            chipAndSpace: supported.chipAndSpace, supported: true,
+            spaceShortfall: .insufficientSpace(
+              requiredBytes: 76_562_825_216, availableBytes: 73_528_246_272)),
+          false, true
+        ),
+        (
+          "not ready",
+          HostDisplay(
+            chipAndSpace: supported.chipAndSpace, supported: false,
+            blockingReason: "The installer engine is unavailable."),
+          false, nil
+        ),
+        (
+          "model not in the catalog",
+          HostDisplay(
+            chipAndSpace: "Apple M3 · 400 GB free", supported: false,
+            unsupportedModel: UnsupportedModelDisplay(
+              deviceIdentifier: "apple,j504", modelIdentifier: "Mac15,3",
+              supportedDeviceIdentifiers: ["apple,j314s"])),
+          false, false
+        ),
+        ("blocked model", HostDisplay(chipAndSpace: "Apple M4 Pro", supported: false), true, false),
+      ]
+      for (name, host, blocked, expected) in cases {
+        let environment = MockInstallerEnvironment()
+        environment.host = host
+        environment.installationBlocked = blocked
+        let session = InstallerSession(environment: environment)
+        await session.inspect()
+        XCTAssertEqual(session.modelSupported, expected, name)
+      }
+    }
+
     func testReinspectResetsDisplayedAndStoredEncryptionChoice() async {
       let environment = MockInstallerEnvironment()
       let session = InstallerSession(environment: environment)