docs: PowerPoint deck for internal admin + end-user guide, embedded in installer

Two presentations generated from pptxgenjs scripts in docs/, both using
the launcher's dark palette (black bg, #161B23 cards, #3B82F6 blue
accent for internal, #16A34A green accent for the user guide):

- PS_Launcher-Documentation-Interne.pptx (17 slides)
  Cover, sommaire, architecture client/serveur/MySQL, setup OVH initial,
  config.php, génération secrets, backoffice (Dashboard / Licenses /
  Versions / Launcher / Audit), workflow release Proserve, workflow
  release launcher, security (Ed25519 / HMAC / DPAPI), file locations
  + logs, troubleshooting, closing.

- PS_Launcher-Guide-Utilisateur.pptx (14 slides)
  Cover, présentation du launcher, prérequis Windows, installation
  setup.exe (avec gestion SmartScreen), activation license PRSRV-,
  bibliothèque (featured + autres), lancer une version, installer une
  nouvelle version, suivi du DL avec resume, menu ⋯ par version,
  paramètres ⚙, auto-update du launcher, FAQ (license expirée /
  offline / changement PC / SHA-256 KO), support.

Both decks use cards with colored left-accent strips, numbered step
flows, code blocks (Consolas on #0A0E14), and consistent footer
branding "© 2026 ASTERION VR".

installer/PSLauncher.iss now copies the user guide into {app}\docs\
and creates a "Guide utilisateur" Start Menu shortcut next to the
launcher. The internal doc stays in the repo, never shipped to clients.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

installer/PSLauncher.iss

@@ -60,9 +60,11 @@ Name: "desktopicon";   Description: "{cm:CreateDesktopIcon}";   GroupDescription
 [Files]
 Source: "..\src\PSLauncher.App\bin\Release\net8.0-windows10.0.17763.0\win-x64\publish\{#MyAppExeName}";  DestDir: "{app}"; Flags: ignoreversion
 Source: "..\src\PSLauncher.Updater\bin\Release\net8.0-windows\win-x64\publish\{#MyUpdaterExeName}";       DestDir: "{app}"; Flags: ignoreversion
+Source: "..\docs\PS_Launcher-Guide-Utilisateur.pptx";                                                    DestDir: "{app}\docs"; Flags: ignoreversion
 
 [Icons]
 Name: "{group}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"
+Name: "{group}\Guide utilisateur"; Filename: "{app}\docs\PS_Launcher-Guide-Utilisateur.pptx"; IconFilename: "{app}\{#MyAppExeName}"
 Name: "{group}\{cm:UninstallProgram,{#MyAppName}}"; Filename: "{uninstallexe}"
 Name: "{autodesktop}\{#MyAppName}"; Filename: "{app}\{#MyAppExeName}"; Tasks: desktopicon