refactor(collab): remove live document collaboration and enforce strictly read-only sharing

internal/storage/sqlite_test.go

@@ -173,16 +173,10 @@ func TestStoreLifecycle(t *testing.T) {
 		t.Fatalf("expected UpdateDocument to fail for read-only user, but succeeded")
 	}
 
-	// Upgrade to write permission
-	_, err = store.CreateDocShare(user.ID, newDoc.ID, user2.ID, "write")
-	if err != nil {
-		t.Fatalf("Upgrade CreateDocShare failed: %v", err)
-	}
-
-	// user2 edits writeable doc -> must succeed
+	// user2 is a read-only collaborator -> editing must fail
 	_, err = store.UpdateDocument(user2.ID, newDoc.ID, &updatedTitle, nil, nil, nil, nil, nil)
-	if err != nil {
-		t.Fatalf("UpdateDocument failed for write collaborator: %v", err)
+	if err == nil {
+		t.Fatalf("expected UpdateDocument to fail for read-only collaborator, but succeeded")
 	}
 
 	// Remove share
@@ -551,8 +545,7 @@ func TestDatabaseFirstWorkspaceArchitecture(t *testing.T) {
 		t.Fatalf("MoveDocument by userB failed: %v", err)
 	}
 
-	// User B edits the document via PatchDocumentBlocks (modifying b2 and adding b3)
-	// Simultaneously, User A edits b1 and adds b4 using a slightly stale order
+	// User B is a read-only collaborator -> PatchDocumentBlocks must fail
 	_, _, err = store.PatchDocumentBlocks(userB.ID, doc.ID, domain.DocBlocksPatchRequest{
 		Upserted: []domain.DocumentBlock{
 			{ID: "b2", Type: "bullet", Content: "Zeile 2 von B bearbeitet", Level: 0},
@@ -560,8 +553,8 @@ func TestDatabaseFirstWorkspaceArchitecture(t *testing.T) {
 		},
 		BlockOrder: []string{"b1", "b2", "b3"},
 	})
-	if err != nil {
-		t.Fatalf("PatchDocumentBlocks by userB failed: %v", err)
+	if err == nil {
+		t.Fatalf("expected PatchDocumentBlocks by read-only userB to fail, but succeeded")
 	}
 
 	// User A's client only knew about b1, b2 when sending its patch (adds b4)
@@ -576,9 +569,9 @@ func TestDatabaseFirstWorkspaceArchitecture(t *testing.T) {
 		t.Fatalf("PatchDocumentBlocks by userA failed: %v", err)
 	}
 
-	// Verify NO blocks were lost! All 4 blocks (b1, b2, b3, b4) must exist with both users' edits preserved
-	if len(patchedDocA.Blocks) != 4 {
-		t.Fatalf("expected 4 blocks after concurrent patches, got %d: %+v", len(patchedDocA.Blocks), patchedDocA.Blocks)
+	// Verify User A's blocks are preserved: b1, b2, b4 (3 blocks)
+	if len(patchedDocA.Blocks) != 3 {
+		t.Fatalf("expected 3 blocks after patch, got %d: %+v", len(patchedDocA.Blocks), patchedDocA.Blocks)
 	}
 	blockContent := make(map[string]string)
 	for _, b := range patchedDocA.Blocks {
@@ -587,12 +580,6 @@ func TestDatabaseFirstWorkspaceArchitecture(t *testing.T) {
 	if blockContent["b1"] != "Zeile 1 von A bearbeitet" {
 		t.Fatalf("expected b1 updated by A, got %q", blockContent["b1"])
 	}
-	if blockContent["b2"] != "Zeile 2 von B bearbeitet" {
-		t.Fatalf("expected b2 updated by B to be preserved, got %q", blockContent["b2"])
-	}
-	if blockContent["b3"] != "Zeile 3 neu von B" {
-		t.Fatalf("expected b3 added by B to be preserved even with stale order from A, got %q", blockContent["b3"])
-	}
 	if blockContent["b4"] != "Zeile 4 neu von A" {
 		t.Fatalf("expected b4 added by A, got %q", blockContent["b4"])
 	}