Documentation: install/upgrade/uninstall guides + recipes incl. Zerto

Adds a docs/ folder under the repo root with full operator documentation
aimed at sysadmins (not webhook developers). The Zerto pre/post script
recipe is the canonical "why does this exist" walkthrough; the GitHub
HMAC, AD password reset, and UI-on-desktop recipes round out common
patterns.

Pages:
- README.md (index)
- concepts.md (5-minute "what is a webhook" explainer)
- installation.md (interactive + silent install)
- upgrading.md (single-click upgrade flow + edge cases)
- uninstalling.md (clean removal + wiping ProgramData)
- runas-modes.md (Service / InteractiveUser / SpecificUser decision flow)
- service-account-and-ad.md (gMSA setup, delegated rights)
- network-and-security.md (bind addresses, allowlists, HTTPS, secret storage)
- troubleshooting.md (symptom -> first check, common errors)
- recipes/zerto-pre-post-scripts.md (canonical use case)
- recipes/github-style-hmac.md (GitHub / Stripe-shaped webhooks)
- recipes/ad-password-reset.md (gMSA-backed self-service reset)
- recipes/ui-on-desktop.md (InteractiveUser pattern)

Top-level README.md restructured to point at docs/ as the source of
truth, dropping the duplicated installation snippets.

Installer ships docs/ alongside the binaries so they're available
offline at C:\Program Files\WebhookServer\docs\. GUI Help menu gains
a "Documentation" item that opens the docs site in a browser.

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

docs/uninstalling.md

@@ -0,0 +1,90 @@
+# Uninstalling
+
+## TL;DR
+
+**Settings → Apps & features → Webhook Server → Uninstall.** Or right-click the **Uninstall Webhook Server** Start Menu shortcut.
+
+Your endpoints, secrets, and logs in `C:\ProgramData\WebhookServer\` are preserved by default. To wipe those too, see [Below](#wiping-config-and-logs-too).
+
+## What the uninstaller does
+
+In order:
+
+1. **Stops the service** (`net stop WebhookServer`).
+2. **Removes the service** registration via `uninstall-service.ps1` (which calls `sc.exe delete WebhookServer`).
+3. **Deletes** `C:\Program Files\WebhookServer\`.
+4. **Removes** the Start Menu and (if created) Desktop shortcuts.
+5. **Removes** the Programs and Features entry.
+
+What it **does not** touch:
+
+- `C:\ProgramData\WebhookServer\` (config, secrets, log files, auto-snapshots)
+- Any cert in your local cert store you bound HTTPS to
+- Domain accounts / gMSAs the service ran under
+- Endpoints' deployed scripts, if you stored them outside the install dir
+
+## Wiping config and logs too
+
+After running the uninstaller, also remove the data root:
+
+```powershell
+# from elevated PowerShell
+Remove-Item -Recurse -Force "$env:ProgramData\WebhookServer"
+```
+
+This deletes:
+
+- `config.json` (with all your endpoints, encrypted secrets, settings)
+- `backups\` (all auto-snapshots — you can't restore from these once gone)
+- `logs\` (history of every webhook hit)
+
+There's no recovery from this. If you might want to reinstall later with the same configuration, copy `config.json` to a safe location first. Note that **secrets in the saved config can only be decrypted on the same machine** (DPAPI LocalMachine scope) — you can move the file but the bearer/HMAC/RunAs passwords inside become unrecoverable on a different host.
+
+## Silent uninstall
+
+The Programs and Features uninstaller is `unins000.exe` in the install directory:
+
+```powershell
+# from elevated PowerShell
+& "C:\Program Files\WebhookServer\unins000.exe" /VERYSILENT /SUPPRESSMSGBOXES /NORESTART
+```
+
+Same set of preserved/removed paths as the interactive flow.
+
+## Removing only the service, keeping the binaries
+
+If you want to keep the GUI installed but stop running the service (rare, but useful if you're testing):
+
+```powershell
+# from elevated PowerShell
+sc.exe stop WebhookServer
+sc.exe delete WebhookServer
+```
+
+The GUI will show **Disconnected** since there's no service to talk to. Re-create the service later by running `install-service.ps1`:
+
+```powershell
+& "C:\Program Files\WebhookServer\scripts\install-service.ps1" `
+    -BinaryPath "C:\Program Files\WebhookServer\WebhookServer.Service.exe"
+```
+
+## Edge cases
+
+### "The service cannot be stopped because it has not been started."
+
+Harmless. The uninstaller proceeds regardless.
+
+### "Cannot delete: file in use"
+
+A GUI window or other process is holding files in `C:\Program Files\WebhookServer\` open. Close everything and re-run the uninstaller. If that fails, reboot and re-run.
+
+### Programs and Features entry remains after files are gone
+
+If you deleted `C:\Program Files\WebhookServer\` manually before running the uninstaller, `unins000.exe` is gone too and Programs and Features can't run it. Remove the orphan entry by deleting its registry key:
+
+```powershell
+# from elevated PowerShell - dry run to confirm the key exists
+Get-Item 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\{6E3B3C1A-9C20-4F50-B6A8-2B6D6D7E2F11}_is1' -ErrorAction SilentlyContinue
+# if it shows up, delete it:
+Remove-Item 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\{6E3B3C1A-9C20-4F50-B6A8-2B6D6D7E2F11}_is1' -Recurse
+```