Repair files broken by the web-UI merge

The merge of add-backend-api into main committed unresolved conflicts
and corrupted uploads; the API could not import on main.

- backend/app/settings.py, deploy/backup-dashboard-api.service,
  collectors/veeam/README.md: remove conflict markers, restoring the
  add-backend-api versions
- backend/app/__init__.py, backend/tests/__init__.py: were 1024 null
  bytes ("source code string cannot contain null bytes"); now empty
- Remove the accidental Backup-Dashboard gitlink at the repo root and a
  duplicate collectors/veeam/MockVeeam.ps1 (identical to tests/)
- Restore the 60-minute collector interval from 17ee303, which the
  merge reverted to 15, and update the docs to match

Co-Authored-By: Claude Opus 5.5 <[email protected]>

backend/.gitignore

@@ -0,0 +1,8 @@
+__pycache__/
+*.pyc
+.venv/
+venv/
+.pytest_cache/
+*.db
+*.db-wal
+*.db-shm

collectors/veeam/Install-VeeamCollector.ps1

@@ -22,7 +22,7 @@ param(
     [Parameter(Mandatory)][string]$ApiUrl,
     [Parameter(Mandatory)][string]$Tenant,
     [string]$SourceSystem = 'Veeam B&R',
-    [ValidateRange(5, 1440)][int]$IntervalMinutes = 15,
+    [ValidateRange(5, 1440)][int]$IntervalMinutes = 60,
     [ValidateRange(1, 720)][int]$LookbackHours = 48,
     [string]$InstallDir = (Join-Path $env:ProgramFiles 'BackupDashboard'),
     # Defaults to the machine-wide PowerShell 7 install

collectors/veeam/README.md

@@ -20,7 +20,7 @@ account can't run it. The installer checks for this before changing anything.
    It prompts for the key, then:
    - writes `C:\ProgramData\BackupDashboard\veeam-collector.json` (readable only by SYSTEM and Administrators)
    - copies the script to `C:\Program Files\BackupDashboard\`
-   - registers the scheduled task **Backup Dashboard - Veeam collector** (SYSTEM, every 15 minutes,
+   - registers the scheduled task **Backup Dashboard - Veeam collector** (SYSTEM, every 60 minutes,
      run by `C:\Program Files\PowerShell\7\pwsh.exe`; use `-PwshPath` if it's installed elsewhere)
 3. Preview the payloads, then backfill 30 days so the history view is populated straight away
    (from `pwsh`):

collectors/veeam/Send-VeeamBackupStatus.ps1

@@ -3,7 +3,7 @@
     Reports Veeam Backup & Replication job results to the Backup Dashboard.
 
 .DESCRIPTION
-    Runs on the VBR server, normally as a SYSTEM scheduled task every 15 minutes
+    Runs on the VBR server, normally as a SYSTEM scheduled task every 60 minutes
     (see Install-VeeamCollector.ps1). For every backup, replica and backup copy job it sends:
       - the job's next scheduled run (drives the dashboard's Overdue flag), and
       - every session from the last LookbackHours that the dashboard hasn't already received