feat(review): fast keyboard-first Stacks & Duplicates resolve queue

Both tabs get a resolve-and-advance queue instead of independent
click-to-focus cards: ↑/↓ or j/k rove between groups, resolving a
group removes it optimistically and auto-advances focus, and a sticky
header tracks reclaimable bytes + a running "resolved this session"
tally. ⌘Z undoes via a new sidecar restore endpoint (gridKeyNav — the
usual ⌘Z owner — isn't mounted on these tabs, so DuplicatesView wires
its own).

Sidecar (handlers_dups.go, fs.go, main.go):
- POST /duplicates/restore — inverse of /duplicates/archive, moves
  quarantined files back to their original path with the same BasePath
  guards and async reindex-with-cleanup.
- Scan results now include each file's mtime so the UI can label
  older/newer copies.

Stack losers now go through the same sidecar quarantine as
cross-folder duplicates (setPrimary + archiveDuplicatePaths) instead
of a hard PhotoPrism DELETE, so both tabs share one recoverable,
undoable resolution path (services/duplicateActions.svelte.ts).

StackGroupCard: comparison-first — fact rows highlight the best
size/resolution per file, a "Suggested" badge appears when one file
wins outright, and Space opens a fullscreen CompareLightbox that flips
between candidates while preserving zoom/pan (extracted the zoom/pan
gesture handling from PreviewPane into a shared lib/actions/zoomPan.ts
action so both consumers share one implementation).

CrossFolderGroupCard: since every copy is byte-identical, the old grid
of N identical thumbnails told the user nothing — replaced with one
thumbnail plus a path list that highlights the differing folder
segment and flags the indexed/newest copy.

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

sidecar/fs.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 )
 
 // sanitizeFilename trims a user-supplied filename and rejects anything
@@ -168,6 +169,7 @@ type fileEntry struct {
 	RelPath string
 	AbsPath string
 	Size    int64
+	ModTime time.Time
 }
 
 // supportedExts mirrors the Node prototype's whitelist. PhotoPrism
@@ -222,6 +224,7 @@ func walkFiles(root string) ([]fileEntry, error) {
 			RelPath: rel,
 			AbsPath: p,
 			Size:    info.Size(),
+			ModTime: info.ModTime(),
 		})
 		return nil
 	})