Fix history popup row hover spacing

docs/plans/history-list-spacing.md

@@ -0,0 +1,34 @@
+# History List Spacing Plan
+
+## Goal
+Fix the small-window Bridge history popup so adjacent conversation rows no longer visually collide when a row is hovered.
+
+## Current State
+- The macOS 26 small-window header uses `ConversationHistoryLiquidActionGroup` with the `.liquidPopup` conversation list style.
+- Liquid popup conversation rows are spaced tightly, and non-virtualized rows are not forced to the same layout height as their hover/active background.
+- In dense lists, an active row background and the next hovered row background can visually collide because the background extends outside the row's allocated geometry.
+
+## Proposed Changes
+1. Keep the data flow, selection, rename/delete/share actions, shortcuts, and accessibility identifiers unchanged.
+2. Restore the previous compact `.liquidPopup` row height while keeping hover backgrounds contained: 36px rows, 0px adjacent row gaps, and 12px section gaps.
+3. Keep each compact history item to one visible title line by hiding the gray last-message preview text.
+4. Force non-virtualized `.liquidPopup` item rows to use the same fixed row height that the background and virtualization layout use.
+5. Keep the legacy `.menu` style unchanged.
+6. Add regression coverage for the liquid popup row metrics, preview visibility, inter-section spacing, and virtualization layout gaps.
+7. Validate the popup in a small-window history scenario and capture a screenshot.
+
+## What Happens If We Do Not Change It
+Hovering a conversation row in the small-window history popup can still overlap or crowd adjacent rows, making the list feel broken and increasing mis-click risk.
+
+## Expected Result After Change
+Each history item keeps its hover/active background inside its own row box. Adjacent item backgrounds meet without an inserted gap and without visual overlap.
+
+## Acceptance Criteria
+- `.liquidPopup` adjacent rows have a 0px layout gap while each hover/active background stays contained in its own row box.
+- `.liquidPopup` rows do not render the gray last-message preview text.
+- Legacy `.menu` row metrics remain unchanged.
+- Virtualized and non-virtualized liquid list rows use the previous compact height while keeping hover/active backgrounds inside that row box.
+- Section headers keep a clear gap from the previous section's final row background.
+- Existing row actions and selection behavior remain unchanged.
+- Automated coverage passes or any environment blocker is explicitly reported.
+- Manual small-window visual validation produces a screenshot showing separated hover rows.

macos/OpenBridge/Interface/Conversation/ConversationListLiquidVirtualization.swift

@@ -87,16 +87,20 @@ enum ConversationListLiquidVirtualization {
         var cursorY = style.verticalPadding
 
         for (sectionIndex, section) in sections.enumerated() {
-            if sectionIndex > 0, style.showsSectionDivider {
-                rows.append(
-                    Row(
-                        id: "divider-\(sectionIndex)",
-                        minY: cursorY,
-                        height: style.dividerHeight,
-                        kind: .divider
+            if sectionIndex > 0 {
+                if style.showsSectionDivider {
+                    rows.append(
+                        Row(
+                            id: "divider-\(sectionIndex)",
+                            minY: cursorY,
+                            height: style.dividerHeight,
+                            kind: .divider
+                        )
                     )
-                )
-                cursorY += style.dividerHeight
+                    cursorY += style.dividerHeight
+                } else {
+                    cursorY += style.sectionSpacing
+                }
             }
 
             rows.append(

macos/OpenBridge/Interface/Conversation/ConversationListMenu.swift

@@ -1063,7 +1063,21 @@ enum ConversationListPresentationStyle: Equatable {
     }
 
     var rowSpacing: CGFloat {
-        2
+        switch self {
+        case .menu:
+            2
+        case .liquidPopup:
+            0
+        }
+    }
+
+    var sectionSpacing: CGFloat {
+        switch self {
+        case .menu:
+            0
+        case .liquidPopup:
+            12
+        }
     }
 
     var rowHorizontalPadding: CGFloat {
@@ -1094,12 +1108,7 @@ enum ConversationListPresentationStyle: Equatable {
     }
 
     var rowHoverBackgroundHeight: CGFloat {
-        switch self {
-        case .menu:
-            rowHeight
-        case .liquidPopup:
-            38
-        }
+        rowHeight
     }
 
     var rowOuterHorizontalPadding: CGFloat {
@@ -1121,12 +1130,7 @@ enum ConversationListPresentationStyle: Equatable {
     }
 
     var showsPreview: Bool {
-        switch self {
-        case .menu:
-            false
-        case .liquidPopup:
-            true
-        }
+        false
     }
 
     var sectionFont: Font {
@@ -1323,8 +1327,12 @@ struct ConversationListMenuContent: View {
     private func listContent(_ groups: [ConversationListSection]) -> some View {
         VStack(alignment: .leading, spacing: 0) {
             ForEach(Array(groups.enumerated()), id: \.offset) { index, section in
-                if index > 0, style.showsSectionDivider {
-                    Divider().padding(.vertical, 4)
+                if index > 0 {
+                    if style.showsSectionDivider {
+                        Divider().padding(.vertical, 4)
+                    } else if style.sectionSpacing > 0 {
+                        Color.clear.frame(height: style.sectionSpacing)
+                    }
                 }
                 sectionView(section)
             }
@@ -1373,6 +1381,7 @@ struct ConversationListMenuContent: View {
                 ForEach(section.items, id: \.id) { session in
                     sessionRow(session)
                         .padding(.horizontal, style.rowOuterHorizontalPadding)
+                        .frame(height: style.rowHeight)
                 }
             }
         }
@@ -1383,7 +1392,9 @@ struct ConversationListMenuContent: View {
 
         var height: CGFloat = padding
         for (index, section) in groups.enumerated() {
-            if index > 0, style.showsSectionDivider { height += style.dividerHeight }
+            if index > 0 {
+                height += style.showsSectionDivider ? style.dividerHeight : style.sectionSpacing
+            }
             height += style.sectionHeaderHeight
             height += CGFloat(section.items.count) * style.rowHeight
             height += CGFloat(max(section.items.count - 1, 0)) * style.rowSpacing

macos/OpenBridge/Interface/Conversation/ConversationListMenuRowViews.swift

@@ -54,6 +54,7 @@ struct SessionRowButton: View {
                 .padding(.vertical, style.rowVerticalPadding)
         }
         .frame(maxWidth: .infinity, alignment: .leading)
+        .frame(height: style.rowHeight)
         .background(alignment: .center) {
             rowBackground
                 .frame(height: style.rowHoverBackgroundHeight)

macos/OpenBridgeUnitTests/Suites/ConversationListLiquidVirtualizationTests.swift

@@ -1,3 +1,4 @@
+import CoreGraphics
 @testable import OpenBridge
 import Testing
 
@@ -47,7 +48,87 @@ struct ConversationListLiquidVirtualizationTests {
 
         #expect(visibleRows.count < layout.rows.count)
         #expect(visibleRows.first?.id == "session-3")
-        #expect(visibleRows.last?.id == "session-5")
+        #expect(visibleRows.last?.id == "session-6")
+    }
+
+    @Test
+    func `menu row metrics stay compact for legacy history menu`() {
+        let style = ConversationListPresentationStyle.menu
+
+        #expect(style.rowHeight == 30)
+        #expect(style.rowSpacing == 2)
+        #expect(style.sectionSpacing == 0)
+        #expect(style.rowHoverBackgroundHeight == style.rowHeight)
+    }
+
+    @Test
+    func `liquid popup row metrics do not add a gap between adjacent row backgrounds`() {
+        let style = ConversationListPresentationStyle.liquidPopup
+        let hoverOverhang = max(CGFloat.zero, style.rowHoverBackgroundHeight - style.rowHeight)
+        let overlapBetweenAdjacentHoverBackgrounds = hoverOverhang - style.rowSpacing
+
+        #expect(style.rowHeight == 36)
+        #expect(style.rowVerticalPadding == 3)
+        #expect(!style.showsPreview)
+        #expect(style.rowHoverBackgroundHeight <= style.rowHeight)
+        #expect(style.rowSpacing == 0)
+        #expect(overlapBetweenAdjacentHoverBackgrounds <= 0)
+        #expect(style.sectionSpacing >= 12)
+    }
+
+    @Test
+    func `liquid popup layout keeps consecutive session rows hover safe`() {
+        let layout = ConversationListLiquidVirtualization.buildLayout(
+            sections: [
+                ConversationListSection(
+                    title: "today",
+                    items: [
+                        session(id: "a", updatedAt: 300),
+                        session(id: "b", updatedAt: 200),
+                    ]
+                ),
+            ],
+            style: .liquidPopup,
+            includesLoadMoreFooter: false,
+            loadMoreFooterHeight: 28
+        )
+        let sessionRows = layout.rows.filter { row in
+            if case .session = row.kind {
+                return true
+            }
+            return false
+        }
+
+        #expect(sessionRows.count == 2)
+        let gap = sessionRows[1].minY - sessionRows[0].maxY
+        #expect(gap == 0)
+    }
+
+    @Test
+    func `liquid popup layout keeps section headers clear of preceding row hover`() throws {
+        let layout = ConversationListLiquidVirtualization.buildLayout(
+            sections: [
+                ConversationListSection(
+                    title: "yesterday",
+                    items: [
+                        session(id: "recent", updatedAt: 300),
+                    ]
+                ),
+                ConversationListSection(
+                    title: "3w ago",
+                    items: [
+                        session(id: "older", updatedAt: 200),
+                    ]
+                ),
+            ],
+            style: .liquidPopup,
+            includesLoadMoreFooter: false,
+            loadMoreFooterHeight: 28
+        )
+        let recentRow = try #require(layout.rows.first { $0.id == "recent" })
+        let olderHeader = try #require(layout.rows.first { $0.id == "header-1-3w ago" })
+
+        #expect(olderHeader.minY - recentRow.maxY >= ConversationListPresentationStyle.liquidPopup.sectionSpacing)
     }
 
     @Test