fix: orphan detection false positive with dots in directory name

Only treat issue IDs as hierarchical (parent.child) when the dot appears
AFTER the first hyphen. This prevents false positives when the project
directory name contains a dot (e.g., "my.project-abc123" was incorrectly
being treated as having parent "my").

Fixes GH#508

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/storage/sqlite/orphan_handling_test.go

@@ -235,6 +235,131 @@ func TestOrphanHandling_Config(t *testing.T) {
 	}
 }
 
+// TestOrphanHandling_PrefixWithDots tests that prefixes containing dots don't trigger
+// false positives in hierarchical ID detection (GH#508)
+func TestOrphanHandling_PrefixWithDots(t *testing.T) {
+	ctx := context.Background()
+	store, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	// Use a prefix with dots (simulating a directory name like "my.project")
+	if err := store.SetConfig(ctx, "issue_prefix", "my.project"); err != nil {
+		t.Fatalf("Failed to set prefix: %v", err)
+	}
+
+	// Create a top-level issue with a dotted prefix
+	// This should NOT be treated as a hierarchical child
+	issue := &types.Issue{
+		ID:        "my.project-abc123",
+		Title:     "Top-level issue with dotted prefix",
+		Priority:  1,
+		IssueType: "task",
+		Status:    "open",
+	}
+
+	// In strict mode, this should succeed because it's not a hierarchical ID
+	// (the dot is in the prefix, not after the hyphen)
+	err := store.CreateIssuesWithOptions(ctx, []*types.Issue{issue}, "my.project", OrphanStrict)
+	if err != nil {
+		t.Fatalf("Expected success for non-hierarchical ID with dotted prefix, got: %v", err)
+	}
+
+	// Verify the issue was created
+	issues, err := store.SearchIssues(ctx, "", types.IssueFilter{})
+	if err != nil {
+		t.Fatalf("Failed to search issues: %v", err)
+	}
+
+	if len(issues) != 1 {
+		t.Fatalf("Expected 1 issue, got %d", len(issues))
+	}
+
+	if issues[0].ID != "my.project-abc123" {
+		t.Errorf("Expected ID my.project-abc123, got %s", issues[0].ID)
+	}
+}
+
+// TestOrphanHandling_PrefixWithDotsAndChild tests hierarchical children with dotted prefixes
+func TestOrphanHandling_PrefixWithDotsAndChild(t *testing.T) {
+	ctx := context.Background()
+	store, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	// Use a prefix with dots
+	if err := store.SetConfig(ctx, "issue_prefix", "my.project"); err != nil {
+		t.Fatalf("Failed to set prefix: %v", err)
+	}
+
+	// First create the parent
+	parent := &types.Issue{
+		ID:        "my.project-abc123",
+		Title:     "Parent issue",
+		Priority:  1,
+		IssueType: "epic",
+		Status:    "open",
+	}
+
+	err := store.CreateIssuesWithOptions(ctx, []*types.Issue{parent}, "my.project", OrphanStrict)
+	if err != nil {
+		t.Fatalf("Failed to create parent: %v", err)
+	}
+
+	// Now create a child - this IS hierarchical (dot after hyphen)
+	child := &types.Issue{
+		ID:        "my.project-abc123.1",
+		Title:     "Child issue",
+		Priority:  1,
+		IssueType: "task",
+		Status:    "open",
+	}
+
+	err = store.CreateIssuesWithOptions(ctx, []*types.Issue{child}, "my.project", OrphanStrict)
+	if err != nil {
+		t.Fatalf("Expected success for child with existing parent, got: %v", err)
+	}
+
+	// Verify both were created
+	issues, err := store.SearchIssues(ctx, "", types.IssueFilter{})
+	if err != nil {
+		t.Fatalf("Failed to search issues: %v", err)
+	}
+
+	if len(issues) != 2 {
+		t.Fatalf("Expected 2 issues, got %d", len(issues))
+	}
+}
+
+// TestOrphanHandling_PrefixWithDotsOrphanChild tests that orphan detection works correctly
+// with dotted prefixes - should detect orphan when parent doesn't exist
+func TestOrphanHandling_PrefixWithDotsOrphanChild(t *testing.T) {
+	ctx := context.Background()
+	store, cleanup := setupTestDB(t)
+	defer cleanup()
+
+	// Use a prefix with dots
+	if err := store.SetConfig(ctx, "issue_prefix", "my.project"); err != nil {
+		t.Fatalf("Failed to set prefix: %v", err)
+	}
+
+	// Try to create a child without the parent - should fail in strict mode
+	child := &types.Issue{
+		ID:        "my.project-abc123.1", // This IS hierarchical (dot after hyphen)
+		Title:     "Orphan child",
+		Priority:  1,
+		IssueType: "task",
+		Status:    "open",
+	}
+
+	err := store.CreateIssuesWithOptions(ctx, []*types.Issue{child}, "my.project", OrphanStrict)
+	if err == nil {
+		t.Fatal("Expected error for orphan child in strict mode")
+	}
+
+	if !strings.Contains(err.Error(), "parent") {
+		t.Errorf("Expected error about missing parent, got: %v", err)
+	}
+}
+
 // TestOrphanHandling_NonHierarchical tests that non-hierarchical IDs work in all modes
 func TestOrphanHandling_NonHierarchical(t *testing.T) {
 	ctx := context.Background()