fix(mail): search every owned job

Replace ineffective pageSize=100 selectors with a bounded owner-filtered search endpoint for composing and moving linked threads.

JobTrackerApi/Controllers/JobApplicationsController.cs

@@ -15,6 +15,8 @@ using static JobTrackerApi.Services.JobApplicationHelpers;
 
 namespace JobTrackerApi.Controllers
 {
+    public sealed record JobApplicationChoiceDto(int Id, string JobTitle, string CompanyName);
+
     [ApiController]
     // Explicitly authorized. These endpoints are all tenant-scoped user data, so they must not
     // depend on the Auth:Require fallback policy being switched on: a deployment that lost that flag
@@ -2268,6 +2270,31 @@ Job description:
             });
         }
 
+        [HttpGet("choices")]
+        public async Task<ActionResult<List<JobApplicationChoiceDto>>> GetChoices(
+            [FromQuery] string? q = null,
+            [FromQuery] int limit = 20,
+            CancellationToken cancellationToken = default)
+        {
+            limit = Math.Clamp(limit, 1, 50);
+            var query = _db.JobApplications.AsNoTracking()
+                .Where(item => !item.IsDeleted);
+            if (!string.IsNullOrWhiteSpace(q))
+            {
+                var like = $"%{q.Trim()}%";
+                query = query.Where(item =>
+                    EF.Functions.Like(item.JobTitle, like) ||
+                    EF.Functions.Like(item.Company.Name, like));
+            }
+
+            return Ok(await query
+                .OrderByDescending(item => item.DateApplied ?? item.SavedAt)
+                .ThenByDescending(item => item.Id)
+                .Select(item => new JobApplicationChoiceDto(item.Id, item.JobTitle, item.Company.Name))
+                .Take(limit)
+                .ToListAsync(cancellationToken));
+        }
+
         [HttpGet("ai-metrics")]
         [HttpGet("summarizer-metrics")]
         public async Task<ActionResult<AiServiceMetrics>> GetSummarizerMetrics(CancellationToken cancellationToken)