feat: add UpdateAppStatus to the workspace agent API (#22219)

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part of https://github.com/coder/coder/issues/21335  
  
This moves updating app status (used by Tasks) into the workspace agent
API over dRPC. This will allow us to update the status without having to
re-authenticate each time, like we would with an HTTP PATCH request.
  
Further PRs in this stack will pipe these requests thru from the CLI MCP
server to the agentsock and finally to this dRPC call to coderd.

coderd/agentapi/apps_internal_test.go

@@ -0,0 +1,115 @@
+package agentapi
+
+import (
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/coderd/database"
+	"github.com/coder/coder/v2/coderd/util/ptr"
+)
+
+func TestShouldBump(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		prevState  *database.WorkspaceAppStatusState // nil means no previous state
+		newState   database.WorkspaceAppStatusState
+		shouldBump bool
+	}{
+		{
+			name:       "FirstStatusBumps",
+			prevState:  nil,
+			newState:   database.WorkspaceAppStatusStateWorking,
+			shouldBump: true,
+		},
+		{
+			name:       "WorkingToIdleBumps",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateWorking),
+			newState:   database.WorkspaceAppStatusStateIdle,
+			shouldBump: true,
+		},
+		{
+			name:       "WorkingToCompleteBumps",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateWorking),
+			newState:   database.WorkspaceAppStatusStateComplete,
+			shouldBump: true,
+		},
+		{
+			name:       "CompleteToIdleNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateComplete),
+			newState:   database.WorkspaceAppStatusStateIdle,
+			shouldBump: false,
+		},
+		{
+			name:       "CompleteToCompleteNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateComplete),
+			newState:   database.WorkspaceAppStatusStateComplete,
+			shouldBump: false,
+		},
+		{
+			name:       "FailureToIdleNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateFailure),
+			newState:   database.WorkspaceAppStatusStateIdle,
+			shouldBump: false,
+		},
+		{
+			name:       "FailureToFailureNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateFailure),
+			newState:   database.WorkspaceAppStatusStateFailure,
+			shouldBump: false,
+		},
+		{
+			name:       "CompleteToWorkingBumps",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateComplete),
+			newState:   database.WorkspaceAppStatusStateWorking,
+			shouldBump: true,
+		},
+		{
+			name:       "FailureToCompleteNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateFailure),
+			newState:   database.WorkspaceAppStatusStateComplete,
+			shouldBump: false,
+		},
+		{
+			name:       "WorkingToFailureBumps",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateWorking),
+			newState:   database.WorkspaceAppStatusStateFailure,
+			shouldBump: true,
+		},
+		{
+			name:       "IdleToIdleNoBump",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateIdle),
+			newState:   database.WorkspaceAppStatusStateIdle,
+			shouldBump: false,
+		},
+		{
+			name:       "IdleToWorkingBumps",
+			prevState:  ptr.Ref(database.WorkspaceAppStatusStateIdle),
+			newState:   database.WorkspaceAppStatusStateWorking,
+			shouldBump: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			var prevAppStatus database.WorkspaceAppStatus
+			// If there's a previous state, report it first.
+			if tt.prevState != nil {
+				prevAppStatus.ID = uuid.UUID{1}
+				prevAppStatus.State = *tt.prevState
+			}
+
+			didBump := shouldBump(tt.newState, prevAppStatus)
+			if tt.shouldBump {
+				require.True(t, didBump, "wanted deadline to bump but it didn't")
+			} else {
+				require.False(t, didBump, "wanted deadline not to bump but it did")
+			}
+		})
+	}
+}