amend POS895 plan: merge discovery tasks, drop network-dependent test

Pre-flight scan found two things the plan mandated that a reviewer would
rightly flag: Task 1 committed a DiscoverPrintersAsync that threw
NotImplementedException until Task 2 replaced it, and a unit test asserted
an empty result from a real UDP broadcast, which passes on a laptop and
fails on any network with a POS895 on it.

Tasks 1 and 2 are now one task delivering the complete service, and the
network-dependent test is gone. The deterministic bind-failure test still
covers the degradation path. Six tasks now.

Claude-Session: https://claude.ai/code/session_01E6N3P4nSZLtp4BC2LXVref

docs/superpowers/plans/2026-09-03-pos895-integration.md

@@ -19,9 +19,9 @@
 
 ---
 
-### Task 1: Test project, `DiscoveredPrinter.Serial`, and SPRT protocol parsing
+### Task 1: `SprtDiscoveryService`, test project, and `DiscoveredPrinter.Serial`
 
-Creates the test project the later tasks need, adds the one new DTO field, and implements the pure functions of the SPRT protocol so they can be tested without a network.
+Delivers the complete SPRT discovery service: the test project the later tasks need, the one new DTO field, the protocol's pure functions, and the network path.
 
 **Files:**
 - Create: `Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
@@ -32,8 +32,8 @@ Creates the test project the later tasks need, adds the one new DTO field, and i
 - Modify: `Inspectron.Epson.slnx`
 
 **Interfaces:**
-- Consumes: `DiscoveredPrinter` (existing class, `Inspectron.Epson`).
+- Consumes: `DiscoveredPrinter`, `IDiscoveryService` (existing, `Inspectron.Epson`).
-- Produces: `SprtDiscoveryService.BuildProbe()` returning `byte[]`; `SprtDiscoveryService.TryParseReply(byte[] payload, string ipAddress, out DiscoveredPrinter? printer)` returning `bool`. Task 2 uses both. `DiscoveredPrinter.Serial` (`string?`) used by Tasks 1-2.
+- Produces: `SprtDiscoveryService(ILogger? logger = null)`; `SprtDiscoveryService.BuildProbe()` returning `byte[]`; `SprtDiscoveryService.TryParseReply(byte[] payload, string ipAddress, out DiscoveredPrinter? printer)` returning `bool`; a working `DiscoverPrintersAsync`. Task 6 constructs it for DI. `DiscoveredPrinter.Serial` (`string?`).
 
 - [ ] **Step 1: Create the test project**
 
@@ -160,9 +160,27 @@ public class SprtDiscoveryServiceTests
         Assert.True(ok);
         Assert.Equal("", printer!.Serial);
     }
+
+    [Fact]
+    public async Task DiscoverPrintersAsync_returns_empty_when_port_9100_is_taken()
+    {
+        // Hold UDP 9100 so the service cannot bind it. It must degrade, not throw:
+        // ENPC discovery has to keep working when this one cannot start.
+        using var blocker = new System.Net.Sockets.UdpClient();
+        blocker.Client.Bind(new System.Net.IPEndPoint(System.Net.IPAddress.Any, 9100));
+
+        var service = new SprtDiscoveryService();
+        var result = await service.DiscoverPrintersAsync(TimeSpan.FromMilliseconds(200));
+
+        Assert.Empty(result);
+    }
 }
 ```
 
+Note there is deliberately no "nothing answers" test. Asserting an empty list from
+a real broadcast would pass on a developer laptop and fail on any network with a
+POS895 on it, including the print server's own.
+
 - [ ] **Step 3: Run the tests to verify they fail**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
@@ -192,7 +210,10 @@ In `Inspectron.Epson/PreconfiguredDiscoveryService.cs`, inside the object initia
 Create `Inspectron.Epson/SprtDiscoveryService.cs`:
 
 ```csharp
+using System.Net;
+using System.Net.Sockets;
 using System.Text;
+using Microsoft.Extensions.Logging;
 
 namespace Inspectron.Epson;
 
@@ -214,11 +235,20 @@ public class SprtDiscoveryService : IDiscoveryService
 {
     private const string ProbeMagic = "SPRT-Infor";
     private const int MacLength = 17;
+    private const int DiscoveryPort = 3289;
+    private const int ReplyPort = 9100;
 
     /// <summary>Model reported for anything answering SPRT. The reply carries no
     /// model name, and a POS896 is indistinguishable from a POS895 here.</summary>
     public const string SprtModelName = "POS895";
 
+    private readonly ILogger? _logger;
+
+    public SprtDiscoveryService(ILogger? logger = null)
+    {
+        _logger = logger;
+    }
+
     /// <summary>The 13-byte discovery query, byte-identical to EasySet's.</summary>
     public static byte[] BuildProbe()
     {
@@ -265,102 +295,6 @@ public class SprtDiscoveryService : IDiscoveryService
         return true;
     }
 
-    public Task<List<DiscoveredPrinter>> DiscoverPrintersAsync(
-        TimeSpan? timeout = null,
-        Action<DiscoveredPrinter>? onPrinterDiscovered = null)
-    {
-        throw new NotImplementedException("Task 2");
-    }
-}
-```
-
-- [ ] **Step 6: Run the tests to verify they pass**
-
-Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 6 tests.
-
-- [ ] **Step 7: Commit**
-
-```bash
-git add Inspectron.Epson.Tests Inspectron.Epson.slnx Inspectron.Epson/SprtDiscoveryService.cs Inspectron.Epson/DiscoveredPrinter.cs Inspectron.Epson/PreconfiguredDiscoveryService.cs
-git commit -m "add SPRT discovery protocol parsing and test project"
-```
-
----
-
-### Task 2: `SprtDiscoveryService` network path
-
-Broadcasts the probe and collects replies. Binding UDP 9100 can fail when another process holds it; discovery must degrade to empty rather than crash, so ENPC discovery still runs.
-
-**Files:**
-- Modify: `Inspectron.Epson/SprtDiscoveryService.cs`
-- Modify: `Inspectron.Epson.Tests/SprtDiscoveryServiceTests.cs`
-
-**Interfaces:**
-- Consumes: `BuildProbe()`, `TryParseReply(...)` from Task 1.
-- Produces: `SprtDiscoveryService(ILogger? logger = null)` constructor; a working `DiscoverPrintersAsync`. Task 6 constructs it for DI.
-
-- [ ] **Step 1: Write the failing tests**
-
-Append to `Inspectron.Epson.Tests/SprtDiscoveryServiceTests.cs`:
-
-```csharp
-    [Fact]
-    public async Task DiscoverPrintersAsync_returns_empty_when_port_9100_is_taken()
-    {
-        // Hold UDP 9100 so the service cannot bind it. It must degrade, not throw:
-        // ENPC discovery has to keep working when this one cannot start.
-        using var blocker = new System.Net.Sockets.UdpClient();
-        blocker.Client.Bind(new System.Net.IPEndPoint(System.Net.IPAddress.Any, 9100));
-
-        var service = new SprtDiscoveryService();
-        var result = await service.DiscoverPrintersAsync(TimeSpan.FromMilliseconds(200));
-
-        Assert.Empty(result);
-    }
-
-    [Fact]
-    public async Task DiscoverPrintersAsync_returns_empty_when_nothing_answers()
-    {
-        var service = new SprtDiscoveryService();
-        var result = await service.DiscoverPrintersAsync(TimeSpan.FromMilliseconds(300));
-
-        Assert.Empty(result);
-    }
-```
-
-- [ ] **Step 2: Run the tests to verify they fail**
-
-Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj --filter DiscoverPrintersAsync`
-Expected: FAIL with `NotImplementedException: Task 2`.
-
-- [ ] **Step 3: Write the implementation**
-
-In `Inspectron.Epson/SprtDiscoveryService.cs`, add these usings at the top:
-
-```csharp
-using System.Net;
-using System.Net.Sockets;
-using Microsoft.Extensions.Logging;
-```
-
-Add a logger field and constructor above `BuildProbe`:
-
-```csharp
-    private const int DiscoveryPort = 3289;
-    private const int ReplyPort = 9100;
-
-    private readonly ILogger? _logger;
-
-    public SprtDiscoveryService(ILogger? logger = null)
-    {
-        _logger = logger;
-    }
-```
-
-Replace the `NotImplementedException` body of `DiscoverPrintersAsync` with:
-
-```csharp
     public async Task<List<DiscoveredPrinter>> DiscoverPrintersAsync(
         TimeSpan? timeout = null,
         Action<DiscoveredPrinter>? onPrinterDiscovered = null)
@@ -442,23 +376,24 @@ Replace the `NotImplementedException` body of `DiscoverPrintersAsync` with:
 
         return discovered;
     }
+}
 ```
 
-- [ ] **Step 4: Run the tests to verify they pass**
+- [ ] **Step 6: Run the tests to verify they pass**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 8 tests.
+Expected: PASS, 7 tests.
 
-- [ ] **Step 5: Commit**
+- [ ] **Step 7: Commit**
 
 ```bash
-git add Inspectron.Epson/SprtDiscoveryService.cs Inspectron.Epson.Tests/SprtDiscoveryServiceTests.cs
+git add Inspectron.Epson.Tests Inspectron.Epson.slnx Inspectron.Epson/SprtDiscoveryService.cs Inspectron.Epson/DiscoveredPrinter.cs Inspectron.Epson/PreconfiguredDiscoveryService.cs
-git commit -m "implement SPRT discovery broadcast and reply collection"
+git commit -m "add SPRT discovery service for POS895 printers"
 ```
 
 ---
 
-### Task 3: `CompositeDiscoveryService`
+### Task 2: `CompositeDiscoveryService`
 
 Runs several discovery services concurrently and merges their results, so ENPC and SPRT printers appear in one list.
 
@@ -674,7 +609,7 @@ Note the children are called **without** the `onPrinterDiscovered` callback. The
 - [ ] **Step 4: Run the tests to verify they pass**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 13 tests.
+Expected: PASS, 12 tests.
 
 - [ ] **Step 5: Commit**
 
@@ -685,7 +620,7 @@ git commit -m "add CompositeDiscoveryService merging ENPC and SPRT results"
 
 ---
 
-### Task 4: `POS895` printer adapter
+### Task 3: `POS895` printer adapter
 
 The adapter differs from `TM_T30IIITranslated` in exactly three ways, each confirmed on hardware. A recording fake asserts the two that would otherwise fail silently on paper.
 
@@ -696,7 +631,7 @@ The adapter differs from `TM_T30IIITranslated` in exactly three ways, each confi
 
 **Interfaces:**
 - Consumes: `IPrinter` (`Inspectron.Epson.PrintServer.PrintServices`), `IEpsonPrinter` (`Inspectron.Epson`), `PrintCommand` (`Inspectron.Epson.PrintServer.Printers.Utils`).
-- Produces: `POS895(IEpsonPrinter printer)` with a `bool SkipDelays { get; set; }`. Task 5 constructs it.
+- Produces: `POS895(IEpsonPrinter printer)` with a `bool SkipDelays { get; set; }`. Task 4 constructs it.
 
 - [ ] **Step 1: Write the recording test double**
 
@@ -1026,7 +961,7 @@ Note `PrintAsync` feeds 10 lines at the end **and** 10 on an `IsCut` command, ma
 - [ ] **Step 5: Run the tests to verify they pass**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 20 tests.
+Expected: PASS, 19 tests.
 
 - [ ] **Step 6: Commit**
 
@@ -1037,7 +972,7 @@ git commit -m "add POS895 printer adapter with LF feed and ESC * logo"
 
 ---
 
-### Task 5: Register printer ID `0x20` in the three switches
+### Task 4: Register printer ID `0x20` in the three switches
 
 Three one-line additions in three files. The third is the one that fails silently if missed.
 
@@ -1048,7 +983,7 @@ Three one-line additions in three files. The third is the one that fails silentl
 - Create: `Inspectron.Epson.Tests/PrinterRegistrationTests.cs`
 
 **Interfaces:**
-- Consumes: `POS895` from Task 4.
+- Consumes: `POS895` from Task 3.
 - Produces: nothing new; wires `0x20` into existing dispatch.
 
 - [ ] **Step 1: Write the failing tests**
@@ -1184,7 +1119,7 @@ Leave `EReceiptType.NextCourse` at `33, 20`. It is hardcoded for every printer a
 - [ ] **Step 6: Run the tests to verify they pass**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 25 tests.
+Expected: PASS, 24 tests.
 
 - [ ] **Step 7: Commit**
 
@@ -1195,7 +1130,7 @@ git commit -m "register printer id 0x20 as POS895 across the three dispatch poin
 
 ---
 
-### Task 6: Guard the nullable printer ID
+### Task 5: Guard the nullable printer ID
 
 `printerId` is a `byte?` dereferenced with `.Value` twice. A printer that does not answer `GS I 1` throws `NullReferenceException` into the generic catch, reporting `PrintErrorType.Other` and burning three `PrinterQueue` retries with no usable log line.
 
@@ -1230,7 +1165,7 @@ Expected: `0 Error(s)`, and no new warnings attributable to `EpsonPrintService.c
 - [ ] **Step 3: Run the full test suite**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 25 tests.
+Expected: PASS, 24 tests.
 
 - [ ] **Step 4: Commit**
 
@@ -1241,7 +1176,7 @@ git commit -m "fail cleanly when a printer does not answer GS I 1"
 
 ---
 
-### Task 7: DI wiring and emulation entry
+### Task 6: DI wiring and emulation entry
 
 Binds the composite discovery in production and adds a 576px emulated POS895 so receipt layouts can be checked without hardware.
 
@@ -1249,7 +1184,7 @@ Binds the composite discovery in production and adds a 576px emulated POS895 so
 - Modify: `EpsonPrintService/PrintServerBootstrapper.cs:52-78`
 
 **Interfaces:**
-- Consumes: `SprtDiscoveryService` (Task 2), `CompositeDiscoveryService` (Task 3).
+- Consumes: `SprtDiscoveryService` (Task 1), `CompositeDiscoveryService` (Task 2).
 - Produces: nothing new.
 
 - [ ] **Step 1: Add the emulated POS895**
@@ -1313,7 +1248,7 @@ Expected: `0 Error(s)`.
 - [ ] **Step 4: Run the full test suite**
 
 Run: `dotnet test Inspectron.Epson.Tests/Inspectron.Epson.Tests.csproj`
-Expected: PASS, 25 tests.
+Expected: PASS, 24 tests.
 
 - [ ] **Step 5: Verify discovery against the real printer**