fix: constrain dialog content to the viewport

- Add dynamic viewport bounds and scrollable body regions to dialogs and modals\n- Make tool-launch popups use the shared scrollable body pattern\n- Keep mobile sheets, action sheets, and notification popups scroll-contained\n- Restore the ProjectsPage test setup required for the frontend suite\n\nOpenSpec: fix-dialog-scroll-containment\nQuality gates: npm run typecheck, npm run lint, npm test (88 passed), npm run build

apps/web/src/styles/global.css

@@ -453,12 +453,16 @@
 	backdrop-filter: blur(2px);
 }
 
-.dialog {
+.dialog,
+.modal-content,
+.commit-dialog {
 	width: 100%;
 	max-width: 32rem;
 	max-height: calc(100vh - var(--space-8));
+	max-height: calc(100dvh - var(--space-8));
 	display: flex;
 	flex-direction: column;
+	min-height: 0;
 	overflow: hidden;
 	background: var(--panel);
 	border: 1px solid var(--border);
@@ -468,16 +472,6 @@
 
 .modal-content {
 	/* deprecated alias */
-	width: 100%;
-	max-width: 32rem;
-	max-height: calc(100vh - var(--space-8));
-	display: flex;
-	flex-direction: column;
-	overflow: hidden;
-	background: var(--panel);
-	border: 1px solid var(--border);
-	border-radius: var(--radius-lg);
-	box-shadow: var(--shadow-xl);
 }
 
 .dialog-lg {
@@ -500,9 +494,13 @@
 	line-height: var(--line-height-tight);
 }
 
-.dialog-body {
+.dialog-body,
+.modal-body {
 	flex: 1;
+	min-height: 0;
 	overflow: auto;
+	overscroll-behavior: contain;
+	-webkit-overflow-scrolling: touch;
 	padding: var(--space-4);
 }
 
@@ -543,9 +541,11 @@
 	}
 
 	.dialog,
-	.modal-content {
+	.modal-content,
+	.commit-dialog {
 		max-width: 100%;
 		max-height: calc(100vh - var(--space-6));
+		max-height: calc(100dvh - var(--space-6));
 		border-radius: var(--radius-lg) var(--radius-lg) 0 0;
 	}
 }