feat: canonical job pipeline as single source of truth

New JobPipeline: ordered canonical stages (Applied, Waiting, Interview,
Offer, Rejected, Ghosted) with category grouping and a Normalize() that
canonicalizes casing and known synonyms (Interviewing->Interview,
declined->Rejected, ...) while preserving unknown custom statuses.

- normalize status on every write path (Create/Update/PATCH status) so
  the stored value stays canonical without destroying custom values
- GET /api/jobapplications/pipeline exposes the ordered stages so the UI
  renders from one source instead of duplicated hardcoded lists
- 14 unit tests; full backend suite green (120)

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

JobTrackerApi.Tests/JobPipelineTests.cs

@@ -0,0 +1,54 @@
+using JobTrackerApi.Services;
+using Xunit;
+
+namespace JobTrackerApi.Tests;
+
+public sealed class JobPipelineTests
+{
+    [Theory]
+    [InlineData("applied", "Applied")]
+    [InlineData("APPLIED", "Applied")]
+    [InlineData("  Offer  ", "Offer")]
+    [InlineData("Interviewing", "Interview")]
+    [InlineData("interviews", "Interview")]
+    [InlineData("declined", "Rejected")]
+    [InlineData("no response", "Ghosted")]
+    public void Normalize_canonicalizes_casing_and_synonyms(string input, string expected)
+        => Assert.Equal(expected, JobPipeline.Normalize(input));
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData(null)]
+    public void Normalize_empty_becomes_default(string? input)
+        => Assert.Equal("Applied", JobPipeline.Normalize(input));
+
+    [Fact]
+    public void Normalize_preserves_unknown_custom_status()
+        => Assert.Equal("Take-home assignment", JobPipeline.Normalize("  Take-home assignment  "));
+
+    [Fact]
+    public void Stages_are_ordered_and_unique()
+    {
+        var orders = JobPipeline.Stages.Select(s => s.Order).ToList();
+        Assert.Equal(orders.OrderBy(x => x), orders);
+        Assert.Equal(orders.Count, orders.Distinct().Count());
+    }
+
+    [Fact]
+    public void OrderOf_sorts_canonical_before_custom()
+    {
+        Assert.True(JobPipeline.OrderOf("Applied") < JobPipeline.OrderOf("Offer"));
+        Assert.True(JobPipeline.OrderOf("Offer") < JobPipeline.OrderOf("Custom stage"));
+        Assert.Equal(JobPipeline.OrderOf("Interview"), JobPipeline.OrderOf("Interviewing"));
+    }
+
+    [Fact]
+    public void IsCanonical_only_true_for_known_stages()
+    {
+        Assert.True(JobPipeline.IsCanonical("Offer"));
+        Assert.True(JobPipeline.IsCanonical("offer"));
+        Assert.False(JobPipeline.IsCanonical("Interviewing")); // synonym, not canonical
+        Assert.False(JobPipeline.IsCanonical("Whatever"));
+    }
+}

JobTrackerApi/Controllers/JobApplicationsController.cs

@@ -1416,7 +1416,7 @@ Canonical profile:
                 OwnerUserId = string.IsNullOrWhiteSpace(userId) ? null : userId,
                 JobTitle = title,
                 CompanyId = request.CompanyId,
-                Status = string.IsNullOrWhiteSpace(request.Status) ? "Applied" : request.Status.Trim(),
+                Status = JobPipeline.Normalize(request.Status),
                 Location = string.IsNullOrWhiteSpace(request.Location) ? null : request.Location.Trim(),
                 Salary = string.IsNullOrWhiteSpace(request.Salary) ? null : request.Salary.Trim(),
                 NextAction = string.IsNullOrWhiteSpace(request.NextAction) ? null : request.NextAction.Trim(),
@@ -1519,7 +1519,7 @@ Canonical profile:
 
             job.JobTitle = title;
             job.CompanyId = request.CompanyId;
-            job.Status = string.IsNullOrWhiteSpace(request.Status) ? job.Status : request.Status.Trim();
+            job.Status = string.IsNullOrWhiteSpace(request.Status) ? job.Status : JobPipeline.Normalize(request.Status);
             job.ResponseReceived = request.ResponseReceived;
             job.ResponseDate = request.ResponseDate;
             job.Location = string.IsNullOrWhiteSpace(request.Location) ? null : request.Location.Trim();
@@ -1572,6 +1572,13 @@ Canonical profile:
 
         public sealed record UpdateStatusRequest(string Status);
 
+        public sealed record PipelineStageDto(string Key, int Order, string Category);
+
+        /// <summary>Canonical ordered pipeline stages so the UI renders one source of truth.</summary>
+        [HttpGet("pipeline")]
+        public ActionResult<IEnumerable<PipelineStageDto>> GetPipeline()
+            => Ok(JobPipeline.Stages.Select(s => new PipelineStageDto(s.Key, s.Order, s.Category.ToString())));
+
         [HttpPatch("{id:int}/status")]
         public async Task<IActionResult> UpdateStatus([FromRoute] int id, [FromBody] UpdateStatusRequest request, CancellationToken cancellationToken)
         {
@@ -1580,7 +1587,7 @@ Canonical profile:
 
             if (string.IsNullOrWhiteSpace(request.Status)) return BadRequest("Status is required.");
             var old = job.Status;
-            job.Status = request.Status.Trim();
+            job.Status = JobPipeline.Normalize(request.Status);
             if (!string.Equals(old, job.Status, StringComparison.OrdinalIgnoreCase))
             {
                 _db.JobEvents.Add(new JobEvent

JobTrackerApi/Services/JobPipeline.cs

@@ -0,0 +1,75 @@
+namespace JobTrackerApi.Services
+{
+    public enum PipelineCategory
+    {
+        Active,
+        Success,
+        Closed,
+    }
+
+    public sealed record PipelineStage(string Key, int Order, PipelineCategory Category);
+
+    /// <summary>
+    /// Canonical job-application pipeline: the single source of truth for the ordered set of
+    /// statuses, their grouping, and how free-text/legacy values normalize onto them.
+    /// Status remains a free-text column so custom values are never destroyed; this only
+    /// canonicalizes casing and known synonyms.
+    /// </summary>
+    public static class JobPipeline
+    {
+        public const string DefaultStatus = "Applied";
+
+        public static readonly IReadOnlyList<PipelineStage> Stages = new List<PipelineStage>
+        {
+            new("Applied", 1, PipelineCategory.Active),
+            new("Waiting", 2, PipelineCategory.Active),
+            new("Interview", 3, PipelineCategory.Active),
+            new("Offer", 4, PipelineCategory.Success),
+            new("Rejected", 5, PipelineCategory.Closed),
+            new("Ghosted", 6, PipelineCategory.Closed),
+        };
+
+        private static readonly Dictionary<string, string> Canonical =
+            Stages.ToDictionary(s => s.Key, s => s.Key, StringComparer.OrdinalIgnoreCase);
+
+        // Legacy/synonym spellings that should collapse onto a canonical stage.
+        private static readonly Dictionary<string, string> Aliases = new(StringComparer.OrdinalIgnoreCase)
+        {
+            ["interviewing"] = "Interview",
+            ["interviews"] = "Interview",
+            ["interviewed"] = "Interview",
+            ["in interview"] = "Interview",
+            ["awaiting response"] = "Waiting",
+            ["awaiting"] = "Waiting",
+            ["in progress"] = "Waiting",
+            ["pending"] = "Waiting",
+            ["no response"] = "Ghosted",
+            ["no reply"] = "Ghosted",
+            ["declined"] = "Rejected",
+        };
+
+        /// <summary>
+        /// Returns the canonical status for a raw value: trims, matches a stage case-insensitively,
+        /// or maps a known synonym. Unknown non-empty values are preserved (trimmed) so custom
+        /// statuses survive. Empty/whitespace becomes the default stage.
+        /// </summary>
+        public static string Normalize(string? status)
+        {
+            var trimmed = (status ?? string.Empty).Trim();
+            if (trimmed.Length == 0) return DefaultStatus;
+            if (Canonical.TryGetValue(trimmed, out var canonical)) return canonical;
+            if (Aliases.TryGetValue(trimmed, out var alias)) return alias;
+            return trimmed;
+        }
+
+        public static bool IsCanonical(string? status)
+            => !string.IsNullOrWhiteSpace(status) && Canonical.ContainsKey(status.Trim());
+
+        public static int OrderOf(string? status)
+        {
+            var normalized = Normalize(status);
+            var stage = Stages.FirstOrDefault(s => string.Equals(s.Key, normalized, StringComparison.OrdinalIgnoreCase));
+            return stage?.Order ?? int.MaxValue; // custom statuses sort last
+        }
+    }
+}