feat(settings): surface the near-duplicate (pHash) control + reorder import tab

The phash_threshold knob (controls whether edits/variants of an image are
dropped as near-duplicates on import) was buried at the bottom of the import
filters form and labelled opaquely, so it read as 'missing'. Hoist it to the
TOP of the form as a 'Near-duplicate sensitivity' section: a labelled slider
(Exact / Strict / Default / Loose stops, 0-16) for the gist + the precise
number field, both bound to phash_threshold, with copy that says plainly to
lower it if variants are being dropped.

Also swap the import-tab order to filters → trigger → recent-tasks (filters on
top per operator); the task list stays directly under the trigger for hit/miss
feedback adjacency.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/views/SettingsView.vue

@@ -44,14 +44,15 @@
       </v-window-item>
 
       <v-window-item value="import">
-        <!-- Order: trigger → recent tasks → filters. Tasks sit directly
-             below the trigger so operator sees hit/miss feedback without
-             scrolling past the filter card (operator-flagged 2026-05-25). -->
+        <!-- Order: filters → trigger → recent tasks. Filters hoisted above the
+             trigger (operator-flagged 2026-06-04); the task list stays
+             directly below the trigger so hit/miss feedback is adjacent to the
+             button that produced it (operator-flagged 2026-05-25). -->
+        <ImportFiltersForm />
+        <v-divider class="my-6" />
         <ImportTriggerPanel />
         <v-divider class="my-6" />
         <ImportTaskList />
-        <v-divider class="my-6" />
-        <ImportFiltersForm />
       </v-window-item>
 
       <v-window-item value="cleanup">