ui(sidebar): split editable vs read-only between Edit and Metadata

The Metadata collapsible was hosting two editable widgets (TagsEditor
and TakenAtEditor) buried inside the readonly sub-sections — Tags as
its own Section, taken-at wedged into Basic Info between size/dims
and the filepath. With both top-level collapsibles in place, the
clearer split is editable up top, readonly below.

Moved into the Edit collapsible (in identification → description →
categorization order):
  Filename, Title, Date Taken, Notes, Tags, Rating, Color, Flag

Metadata now holds only readonly sub-sections:
  Basic Info (size, dims, path), Camera, Location

Dropped the now-empty Tags Section from Metadata and the 'tags' key
from the default-expanded set.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/sidebar/PhotoInfoPanel.tsx

@@ -143,7 +143,7 @@ export function PhotoInfoPanel({ photoId, darkTheme = false }: PhotoInfoPanelPro
   const queryClient = useQueryClient()
 
   const [expandedSections, setExpandedSections] = useState<Set<string>>(
-    new Set(['edit', 'metadata', 'basic', 'camera', 'location', 'tags'])
+    new Set(['edit', 'metadata', 'basic', 'camera', 'location'])
   )
   const toggleSection = (section: string) => {
     const next = new Set(expandedSections)
@@ -447,6 +447,14 @@ export function PhotoInfoPanel({ photoId, darkTheme = false }: PhotoInfoPanelPro
           />
         </div>
 
+        <TakenAtEditor
+          photo={photo}
+          draft={takenAtDraft}
+          onDraftChange={setTakenAtDraft}
+          onCommit={commitTakenAt}
+          darkTheme={darkTheme}
+        />
+
         <div>
           <label className="mb-1 block text-xs text-text-muted">Notes</label>
           <Textarea
@@ -459,6 +467,22 @@ export function PhotoInfoPanel({ photoId, darkTheme = false }: PhotoInfoPanelPro
           />
         </div>
 
+        <div>
+          <label className="mb-1 block text-xs text-text-muted">Tags</label>
+          <TagsEditor
+            photoTags={photo.tags ?? []}
+            allTags={allTags}
+            tagInput={tagInput}
+            onTagInputChange={setTagInput}
+            onAttachExisting={(id) => attachExistingTagMutation.mutate(id)}
+            onCreateAndAttach={(name) => {
+              addTagMutation.mutate(name)
+              setTagInput('')
+            }}
+            onRemove={(id) => removeTagMutation.mutate(id)}
+          />
+        </div>
+
         {/* Rating */}
         <div>
           <label className="mb-1 block text-xs text-text-muted">Rating</label>
@@ -581,25 +605,6 @@ export function PhotoInfoPanel({ photoId, darkTheme = false }: PhotoInfoPanelPro
           )}
         </CollapsibleTrigger>
         <CollapsibleContent>
-        <Section
-          title="Tags"
-          expanded={expandedSections.has('tags')}
-          onToggle={() => toggleSection('tags')}
-        >
-          <TagsEditor
-            photoTags={photo.tags ?? []}
-            allTags={allTags}
-            tagInput={tagInput}
-            onTagInputChange={setTagInput}
-            onAttachExisting={(id) => attachExistingTagMutation.mutate(id)}
-            onCreateAndAttach={(name) => {
-              addTagMutation.mutate(name)
-              setTagInput('')
-            }}
-            onRemove={(id) => removeTagMutation.mutate(id)}
-          />
-        </Section>
-
         <Section
           title="Basic Info"
           expanded={expandedSections.has('basic')}
@@ -616,13 +621,6 @@ export function PhotoInfoPanel({ photoId, darkTheme = false }: PhotoInfoPanelPro
               }
             />
           </div>
-          <TakenAtEditor
-            photo={photo}
-            draft={takenAtDraft}
-            onDraftChange={setTakenAtDraft}
-            onCommit={commitTakenAt}
-            darkTheme={darkTheme}
-          />
           {/* Filepath spans the full sidebar width — most paths are long
            *  enough that the two-column grid above wraps them painfully.
            *  Mono so each character lines up under the next, break-all