Adds 2 units and docs for unit 3. nfr-requirements plan

src/SlpModularCms.Modules.Master/Controllers/CmsInstanceController.cs

@@ -0,0 +1,51 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SlpModularCms.Modules.Master.Models;
+using SlpModularCms.Modules.Master.Services;
+
+namespace SlpModularCms.Modules.Master.Controllers;
+
+[ApiController]
+[Route("[controller]")]
+[Authorize(Policy = "OwnerOnly")]
+public class CmsInstanceController(ICmsInstanceService service) : ControllerBase
+{
+    [HttpGet]
+    public async Task<IActionResult> GetAll()
+    {
+        var instances = await service.GetAllAsync();
+        return Ok(instances);
+    }
+
+    [HttpPost]
+    public async Task<IActionResult> Add([FromBody] CreateCmsInstanceRequest request)
+    {
+        try
+        {
+            var dto = await service.AddAsync(request);
+            return CreatedAtAction(nameof(GetAll), null, dto);
+        }
+        catch (ArgumentException ex)
+        {
+            return BadRequest(new { error = ex.Message });
+        }
+    }
+
+    [HttpPut("{id:guid}/status")]
+    public async Task<IActionResult> UpdateStatus(Guid id, [FromBody] UpdateStatusRequest request)
+    {
+        try
+        {
+            var result = await service.UpdateStatusAsync(id, request);
+            return Ok(result);
+        }
+        catch (KeyNotFoundException ex)
+        {
+            return NotFound(new { error = ex.Message });
+        }
+        catch (ArgumentException ex)
+        {
+            return BadRequest(new { error = ex.Message });
+        }
+    }
+}