RMSPDF dialog shows 0 releases - no error feedback when API fails

Description

When launching RMSPDF from a drawing associated with a job number (e.g., 95959), the PDF Plot Selection dialog shows "Loaded 0 releases" even though the job number is detected from the drawing path. There's no feedback about why no releases were loaded.

Steps to Reproduce

1. Open a drawing in a job folder (e.g., 95959 - JobName/5. Fabrication/...)
2. Run RMSPDF command
3. Dialog opens showing "Loaded 0 releases"
4. The Releases list is empty
5. No error message explains why

Expected Behavior

• If the job has releases in the database, they should appear in the Releases list
• If the API call fails, an error message should be displayed
• If the job has no releases, a clear message should indicate this

Current Behavior

The dialog silently shows empty results. The API client methods catch exceptions and return empty lists without surfacing error information to the user:

// RmsApiClient.cs:786-818
public async Task<List<string>> GetJobsWithReleasesAsync()
{
    // ... catches exceptions and returns empty list
    // LastError is set but never displayed to user
}

Root Cause Analysis

1. LoadJobsAsync() calls GetJobsWithReleasesAsync() which hits /api/releases/jobs
2. If this returns empty or fails, the combo box has no jobs to select
3. Even though the job number is detected from the drawing path, it's not in AvailableJobs so it can't be selected
4. Error information is stored in _apiClient.LastError but not displayed in the UI

Suggested Fix

1. Display _apiClient.LastError in the StatusMessage when API calls fail
2. If detected job number isn't in the available jobs list, show a warning
3. Consider allowing manual job number entry or auto-loading releases for detected job
4. Add better feedback: "No releases found for job X" vs "API error: ..."

Affected Files

• [PdfPlotViewModel.cs](RMS.AutoCAD/RMS.AutoCAD.Plugin/Dialogs/PdfPlotViewModel.cs) - LoadJobsAsync(), LoadReleasesAsync()
• [RmsApiClient.cs](RMS.AutoCAD/RMS.AutoCAD.Plugin/Services/RmsApiClient.cs) - GetJobsWithReleasesAsync(), GetReleasesForJobAsync()
• [PdfPlotDialog.xaml.cs](RMS.AutoCAD/RMS.AutoCAD.Plugin/Dialogs/PdfPlotDialog.xaml.cs) - PdfPlotDialog_Loaded

Environment

• AutoCAD 2026
• RMS Plugin (.NET 8)