Add toggle to disable snapshot branching

New "Branch" button next to "Hide Auto" in the search row. When
toggled off: captures have no parentId, sidebar/timeline show a flat
timestamp-sorted list, branch navigators are hidden, and pruning
skips tree-aware protection.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

js/snapshot_manager.js

@@ -44,6 +44,7 @@ let svgClipCounter = 0;        // unique prefix for SVG clipPath IDs
 let sidebarTooltipEl = null;   // tooltip element for sidebar hover previews
 const lastCapturedIdMap = new Map(); // workflowKey -> id of most recent capture (for parentId chaining)
 const activeBranchSelections = new Map(); // forkPointId -> selected child index
+let branchingEnabled = true;
 const sessionWorkflows = new Map(); // workflowKey -> { firstSeen, lastSeen }
 
 // ─── Server API Layer ───────────────────────────────────────────────
@@ -1376,11 +1377,13 @@ async function captureSnapshot(label = "Auto") {
 
     // Determine parentId for branching
     let parentId = null;
+    if (branchingEnabled) {
         if (activeSnapshotId) {
             parentId = activeSnapshotId; // fork from swapped snapshot
         } else if (lastCapturedIdMap.has(workflowKey)) {
             parentId = lastCapturedIdMap.get(workflowKey); // continuation
         }
+    }
 
     const record = {
         id: generateId(),
@@ -1396,6 +1399,7 @@ async function captureSnapshot(label = "Auto") {
 
     try {
         await db_put(record);
+        if (branchingEnabled) {
             // Compute protected IDs: ancestors of this capture + fork points
             const allRecs = await db_getAllForWorkflow(workflowKey);
             const tempTree = buildSnapshotTree(allRecs);
@@ -1406,6 +1410,9 @@ async function captureSnapshot(label = "Auto") {
             }
             ancestors.add(record.id); // protect the just-captured snapshot
             await pruneSnapshots(workflowKey, [...ancestors]);
+        } else {
+            await pruneSnapshots(workflowKey);
+        }
     } catch {
         return false;
     }
@@ -1441,11 +1448,13 @@ async function captureNodeSnapshot(label = "Node Trigger") {
 
     // Determine parentId for branching
     let parentId = null;
+    if (branchingEnabled) {
         if (activeSnapshotId) {
             parentId = activeSnapshotId;
         } else if (lastCapturedIdMap.has(workflowKey)) {
             parentId = lastCapturedIdMap.get(workflowKey);
         }
+    }
 
     const record = {
         id: generateId(),
@@ -1462,6 +1471,7 @@ async function captureNodeSnapshot(label = "Node Trigger") {
 
     try {
         await db_put(record);
+        if (branchingEnabled) {
             // Compute protected IDs: ancestors + fork points
             const allRecs = await db_getAllForWorkflow(workflowKey);
             const tempTree = buildSnapshotTree(allRecs);
@@ -1471,6 +1481,9 @@ async function captureNodeSnapshot(label = "Node Trigger") {
             }
             protectedNodeIds.add(record.id);
             await pruneNodeSnapshots(workflowKey, [...protectedNodeIds]);
+        } else {
+            await pruneNodeSnapshots(workflowKey);
+        }
     } catch {
         return false;
     }
@@ -2660,9 +2673,22 @@ async function buildSidebar(el) {
         filterItems(searchInput.value.toLowerCase());
     });
 
+    const branchToggleBtn = document.createElement("button");
+    branchToggleBtn.className = "snap-filter-auto-btn active";
+    branchToggleBtn.textContent = "Branch";
+    branchToggleBtn.title = "Toggle snapshot branching";
+    branchToggleBtn.addEventListener("click", async () => {
+        branchingEnabled = !branchingEnabled;
+        branchToggleBtn.classList.toggle("active", branchingEnabled);
+        activeBranchSelections.clear();
+        if (sidebarRefresh) await sidebarRefresh().catch(() => {});
+        if (timelineRefresh) await timelineRefresh().catch(() => {});
+    });
+
     searchRow.appendChild(searchInput);
     searchRow.appendChild(searchClear);
     searchRow.appendChild(autoFilterBtn);
+    searchRow.appendChild(branchToggleBtn);
 
     // Workflow selector
     const selectorRow = document.createElement("div");
@@ -3042,21 +3068,26 @@ async function buildSidebar(el) {
             return;
         }
 
+        let records;
+        let tree = null;
+        let forkPointIds = new Set();
+        if (branchingEnabled) {
             // Build tree and get display path for current branch
-        const tree = buildSnapshotTree(allRecords);
+            tree = buildSnapshotTree(allRecords);
             const displayPath = getDisplayPath(tree, activeBranchSelections);
-        // newest first for display
+            records = [...displayPath].reverse();
-        const records = [...displayPath].reverse();
 
-        // Build set of fork point IDs and record positions for branch nav insertion
-        const forkPointIds = new Set();
             for (const [parentId, children] of tree.childrenOf) {
                 if (children.length > 1) forkPointIds.add(parentId);
             }
+        } else {
+            // Flat: all records newest-first
+            records = [...allRecords].sort((a, b) => b.timestamp - a.timestamp);
+        }
 
         for (const rec of records) {
             // Insert branch navigator above fork-point snapshots
-            if (forkPointIds.has(rec.id)) {
+            if (branchingEnabled && forkPointIds.has(rec.id)) {
                 const children = tree.childrenOf.get(rec.id);
                 const selectedIndex = Math.min(activeBranchSelections.get(rec.id) ?? 0, children.length - 1);
                 const nav = buildBranchNavigator(rec.id, children, selectedIndex, refresh);
@@ -3234,6 +3265,7 @@ async function buildSidebar(el) {
                     if (!confirmed) return;
                 }
                 // Fork-point deletion: rebuild tree from fresh data, then re-parent children
+                if (branchingEnabled) {
                     const freshRecords = await db_getAllForWorkflow(rec.workflowKey);
                     const freshTree = buildSnapshotTree(freshRecords);
                     const children = freshTree.childrenOf.get(rec.id);
@@ -3247,6 +3279,7 @@ async function buildSidebar(el) {
                             await db_updateMeta(rec.workflowKey, child.id, { parentId: newParent });
                         }
                     }
+                }
                 await db_delete(rec.workflowKey, rec.id);
                 pickerDirty = true;
                 await refresh();
@@ -3430,15 +3463,21 @@ function buildTimeline() {
             return;
         }
 
+        let records;
+        let tree = null;
+        let forkPointSet = new Set();
+        if (branchingEnabled) {
             // Show only current branch's markers
-        const tree = buildSnapshotTree(allRecords);
+            tree = buildSnapshotTree(allRecords);
-        const records = getDisplayPath(tree, activeBranchSelections);
+            records = getDisplayPath(tree, activeBranchSelections);
 
-        // Identify fork points on this path
-        const forkPointSet = new Set();
             for (const [parentId, children] of tree.childrenOf) {
                 if (children.length > 1) forkPointSet.add(parentId);
             }
+        } else {
+            // Flat: all records in timestamp order
+            records = [...allRecords].sort((a, b) => a.timestamp - b.timestamp);
+        }
 
         for (const rec of records) {
             const marker = document.createElement("div");
@@ -3481,8 +3520,8 @@ function buildTimeline() {
                 swapSnapshot(rec);
             });
 
-            // Fork point: vertical stack — up arrow, marker with badge, down arrow
+            // Fork point: vertical stack — up arrow, marker, down arrow
-            if (forkPointSet.has(rec.id)) {
+            if (branchingEnabled && forkPointSet.has(rec.id)) {
                 const children = tree.childrenOf.get(rec.id);
                 const selectedIndex = Math.min(activeBranchSelections.get(rec.id) ?? 0, children.length - 1);