feat(review): flag handles in the review player (metadata only)

Renders run 8 frames past the cut at each end. Directors were flagging
glitches in unfixed handles as shot problems, so the player now marks
them — without trimming or burning anything into the EXRs/MOV/MP4.

- Version.handleHead/handleTail/pictureStartFrame, Export.handleHead/
  handleTail; migration backfills pipeline exports and their preview
  versions from the manifest's handleFrames (else 8)
- AE panel: "Includes handles [8] frames each end" -> manifest.review;
  older manifests fall back to source.handleFrames
- finalize copies handles onto the Version; worker 1.6.4 reports the
  head slate length (pictureStartSeconds), else the player infers it
  as MP4 frames - EXR frameCount
- Player: hatched HANDLE / SLATE regions and cut marks on the timeline,
  "HEAD/TAIL HANDLE · NOT IN EDIT" overlay on handle frames, HANDLE badge
  on notes, "Edit range only" toggle (default on in the client portal)
- Staff Handles editor on the review page for manual uploads/corrections

Also fixes two player bugs found while testing: timeToFrame floored
float error (every seek landed a frame early), and J/reverse never ran
(the keyboard effect's cleanup stopped it on the next render).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

components/player/PlaybackControls.tsx

@@ -14,6 +14,7 @@ import {
   Eye,
   EyeOff,
   RectangleHorizontal,
+  Scissors,
 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import {
@@ -74,8 +75,20 @@ export function PlaybackControls({
     setShowAnnotations,
     setAspectPresetId,
     setBlankingMode,
+    editRange,
+    editRangeOnly,
+    setEditRangeOnly,
   } = useReviewStore();
 
+  // Keeping to the edit, the ends of the transport are the cut points.
+  const keepToEdit = editRangeOnly && !!editRange;
+  const goToFrame = (frame: number) => {
+    const video = videoRef.current;
+    if (!video) return;
+    video.pause();
+    video.currentTime = frame / fps;
+  };
+
   const handleRateChange = (val: string) => {
     const rate = parseFloat(val);
     if (videoRef.current) videoRef.current.playbackRate = rate;
@@ -115,13 +128,14 @@ export function PlaybackControls({
                 size="icon-sm"
                 className="text-zinc-400 hover:text-white"
                 onClick={() => {
-                  if (videoRef.current) videoRef.current.currentTime = 0;
+                  if (keepToEdit && editRange) goToFrame(editRange.cutIn);
+                  else if (videoRef.current) videoRef.current.currentTime = 0;
                 }}
               >
                 <ChevronFirst className="h-4 w-4" />
               </Button>
             </TooltipTrigger>
-            <TooltipContent>Go to start</TooltipContent>
+            <TooltipContent>{keepToEdit ? "Go to cut in" : "Go to start"}</TooltipContent>
           </Tooltip>
 
           <Tooltip>
@@ -198,14 +212,15 @@ export function PlaybackControls({
                 size="icon-sm"
                 className="text-zinc-400 hover:text-white"
                 onClick={() => {
-                  if (videoRef.current)
+                  if (keepToEdit && editRange) goToFrame(editRange.tailStart - 1);
+                  else if (videoRef.current)
                     videoRef.current.currentTime = videoRef.current.duration;
                 }}
               >
                 <ChevronLast className="h-4 w-4" />
               </Button>
             </TooltipTrigger>
-            <TooltipContent>Go to end</TooltipContent>
+            <TooltipContent>{keepToEdit ? "Go to cut out" : "Go to end"}</TooltipContent>
           </Tooltip>
         </div>
       </div>
@@ -282,6 +297,32 @@ export function PlaybackControls({
           )}
         </div>
 
+        {/* Edit range only — only for versions with handles marked */}
+        {editRange && (
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <Button
+                variant="ghost"
+                size="icon-sm"
+                className={cn(
+                  "text-zinc-400 hover:text-white",
+                  editRangeOnly && "text-amber-400 bg-amber-400/10"
+                )}
+                onClick={() => setEditRangeOnly(!editRangeOnly)}
+                aria-pressed={editRangeOnly}
+                aria-label="Edit range only"
+              >
+                <Scissors className="h-4 w-4" />
+              </Button>
+            </TooltipTrigger>
+            <TooltipContent>
+              {editRangeOnly
+                ? "Playing the edit only — click to include handles"
+                : "Play the edit only (skip handles)"}
+            </TooltipContent>
+          </Tooltip>
+        )}
+
         {/* Annotation toggle */}
         <Tooltip>
           <TooltipTrigger asChild>