v1.15 — PowerShell edition + repo restructure

- New powershell/InstaSoftOfficeTool.ps1: single-file WPF GUI version
  - Same Fluent Design UI, no compilation needed
  - Runs on any Windows 7+ with PowerShell 5.1 (built-in)
  - Chrome won't flag .ps1 files as "rarely downloaded"
  - Auto-elevates to admin
- Moved C# source to src/ subfolder
- Updated .gitignore for nested bin/obj folders

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app.manifest

@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
-  <assemblyIdentity version="1.0.0.0" name="InstaSoftOfficeTool"/>
-  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
-    <security>
-      <requestedPrivileges xmlns="urn:schemas-microsoft-com:asm.v3">
-        <requestedExecutionLevel level="requireAdministrator" uiAccess="false" />
-      </requestedPrivileges>
-    </security>
-  </trustInfo>
-  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
-    <application>
-      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
-      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
-      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
-      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
-      <supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}" />
-    </application>
-  </compatibility>
-  <application xmlns="urn:schemas-microsoft-com:asm.v3">
-    <windowsSettings>
-      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true/pm</dpiAware>
-      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2</dpiAwareness>
-    </windowsSettings>
-  </application>
-</assembly>