feat(installer): record data directory in install manifest

Write the resolved DbPath parent into the manifest so UninstallRunner
can honour customised data locations instead of always assuming
~/.todo-app. Older manifests fall back to the default path.

src/ClaudeDo.Installer/Core/InstallManifest.cs

@@ -8,7 +8,8 @@ public sealed record InstallManifest(
     string Version,
     string InstallDir,
     string WorkerDir,
-    DateTimeOffset InstalledAt);
+    DateTimeOffset InstalledAt,
+    string? DataDir = null);
 
 public static class InstallManifestStore
 {

src/ClaudeDo.Installer/Core/UninstallRunner.cs

@@ -67,10 +67,13 @@ public sealed class UninstallRunner
                 failures.Add($"install dir ({_context.InstallDirectory}): {err}");
         }
 
-        // 6) Delete ~/.todo-app (config + DB + logs) — only if user opted in.
+        // 6) Delete data dir (config + DB + logs) — only if user opted in.
+        //    Prefer the manifest-recorded DataDir so a customised DbPath is honoured;
+        //    fall back to the default ~/.todo-app for older manifests.
         if (removeAppData)
         {
-            var appData = Paths.AppDataRoot();
+            var manifest = InstallManifestStore.TryRead(_context.InstallDirectory);
+            var appData = manifest?.DataDir ?? Paths.AppDataRoot();
             if (Directory.Exists(appData))
             {
                 progress.Report($"Deleting {appData}...");

src/ClaudeDo.Installer/Steps/WriteInstallManifestStep.cs

@@ -1,4 +1,5 @@
 using System.IO;
+using ClaudeDo.Data;
 using ClaudeDo.Installer.Core;
 
 namespace ClaudeDo.Installer.Steps;
@@ -14,11 +15,14 @@ public sealed class WriteInstallManifestStep : IInstallStep
 
         try
         {
+            var dataDir = Path.GetDirectoryName(Paths.Expand(ctx.DbPath));
+
             var manifest = new InstallManifest(
                 Version: ctx.InstalledVersion,
                 InstallDir: ctx.InstallDirectory,
                 WorkerDir: Path.Combine(ctx.InstallDirectory, "worker"),
-                InstalledAt: DateTimeOffset.UtcNow);
+                InstalledAt: DateTimeOffset.UtcNow,
+                DataDir: dataDir);
 
             InstallManifestStore.Write(ctx.InstallDirectory, manifest);
             progress.Report($"Wrote {InstallManifestStore.ManifestPath(ctx.InstallDirectory)}");