feat: structured salary fields (min/max/currency/period)

Adds SalaryMin/SalaryMax/SalaryCurrency/SalaryPeriod alongside the
existing free-text Salary field (kept for back-compat and display).

- JobApplication model + idempotent column bridging for SQLite and MySQL
- Create/Update DTOs with NormalizeSalary (clamps negatives, swaps
  inverted min/max, uppercases currency, whitelists period)
- JobApplicationDto exposes the fields; CSV export gains 4 columns
- UI: add/edit dialogs get min/max/currency/period inputs; job table
  renders a formatted range via shared salary.ts formatter (falls back
  to free-text when structured values are absent)
- EN/NB translations; backend + full frontend suites green

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

JobTrackerApi/Controllers/ExportController.cs

@@ -58,6 +58,10 @@ namespace JobTrackerApi.Controllers
                     "DateApplied",
                     "Location",
                     "Salary",
+                    "SalaryMin",
+                    "SalaryMax",
+                    "SalaryCurrency",
+                    "SalaryPeriod",
                     "NextAction",
                     "FollowUpAt",
                     "JobUrl",
@@ -76,6 +80,10 @@ namespace JobTrackerApi.Controllers
                         Esc(j.DateApplied.ToString("o")),
                         Esc(j.Location),
                         Esc(j.Salary),
+                        Esc(j.SalaryMin?.ToString(System.Globalization.CultureInfo.InvariantCulture)),
+                        Esc(j.SalaryMax?.ToString(System.Globalization.CultureInfo.InvariantCulture)),
+                        Esc(j.SalaryCurrency),
+                        Esc(j.SalaryPeriod),
                         Esc(j.NextAction),
                         Esc(j.FollowUpAt?.ToString("o")),
                         Esc(j.JobUrl),

JobTrackerApi/Controllers/JobApplicationsController.cs

@@ -749,6 +749,10 @@ Canonical profile:
                 Deadline: job.Deadline,
                 Location: job.Location,
                 Salary: job.Salary,
+                SalaryMin: job.SalaryMin,
+                SalaryMax: job.SalaryMax,
+                SalaryCurrency: job.SalaryCurrency,
+                SalaryPeriod: job.SalaryPeriod,
                 NextAction: job.NextAction,
                 FollowUpAt: job.FollowUpAt,
                 FeedbackRequestedAt: job.FeedbackRequestedAt,
@@ -1081,6 +1085,10 @@ Canonical profile:
             DateTime? Deadline,
             string? Location,
             string? Salary,
+            decimal? SalaryMin,
+            decimal? SalaryMax,
+            string? SalaryCurrency,
+            string? SalaryPeriod,
             string? NextAction,
             DateTime? FollowUpAt,
             DateTime? FeedbackRequestedAt,
@@ -1349,6 +1357,10 @@ Canonical profile:
             string? Status,
             string? Location,
             string? Salary,
+            decimal? SalaryMin,
+            decimal? SalaryMax,
+            string? SalaryCurrency,
+            string? SalaryPeriod,
             string? NextAction,
             DateTime? FollowUpAt,
             string? Notes,
@@ -1367,6 +1379,22 @@ Canonical profile:
             bool? HasOtherAttachment
         );
 
+        private static (decimal? Min, decimal? Max, string? Currency, string? Period) NormalizeSalary(
+            decimal? min, decimal? max, string? currency, string? period)
+        {
+            if (min is < 0) min = null;
+            if (max is < 0) max = null;
+            if (min.HasValue && max.HasValue && min > max) (min, max) = (max, min);
+
+            var cur = (currency ?? "").Trim().ToUpperInvariant();
+            if (cur.Length > 8) cur = cur[..8];
+
+            var per = (period ?? "").Trim().ToLowerInvariant();
+            if (per is not ("year" or "month" or "hour")) per = "";
+
+            return (min, max, cur.Length == 0 ? null : cur, per.Length == 0 ? null : per);
+        }
+
         [HttpPost]
         public async Task<ActionResult<JobApplication>> Create([FromBody] CreateJobApplicationRequest request, CancellationToken cancellationToken)
         {
@@ -1409,6 +1437,9 @@ Canonical profile:
                 ResponseDate = null,
             };
 
+            (job.SalaryMin, job.SalaryMax, job.SalaryCurrency, job.SalaryPeriod) =
+                NormalizeSalary(request.SalaryMin, request.SalaryMax, request.SalaryCurrency, request.SalaryPeriod);
+
             // Generate and persist a short summary at creation time to avoid repeated model calls.
             try
             {
@@ -1447,6 +1478,10 @@ Canonical profile:
             DateTime? ResponseDate,
             string? Location,
             string? Salary,
+            decimal? SalaryMin,
+            decimal? SalaryMax,
+            string? SalaryCurrency,
+            string? SalaryPeriod,
             string? NextAction,
             DateTime? FollowUpAt,
             bool? HasResume,
@@ -1487,6 +1522,8 @@ Canonical profile:
             job.ResponseDate = request.ResponseDate;
             job.Location = string.IsNullOrWhiteSpace(request.Location) ? null : request.Location.Trim();
             job.Salary = string.IsNullOrWhiteSpace(request.Salary) ? null : request.Salary.Trim();
+            (job.SalaryMin, job.SalaryMax, job.SalaryCurrency, job.SalaryPeriod) =
+                NormalizeSalary(request.SalaryMin, request.SalaryMax, request.SalaryCurrency, request.SalaryPeriod);
             job.NextAction = string.IsNullOrWhiteSpace(request.NextAction) ? null : request.NextAction.Trim();
             job.FollowUpAt = request.FollowUpAt;
             job.FeedbackRequestedAt = request.FeedbackRequestedAt;