style: a source's backfill state chips are filled, so their text reads on the dark row

The theme's success and info colours are dark; a tonal chip draws its text in
that colour, which vanished against the Subscriptions row.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/components/subscriptions/SourceCard.vue

@@ -39,18 +39,18 @@
       </v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'running'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
       >{{ source.backfill_bypass_seen ? 'Recovering' : (source.backfill_recapture ? 'Recapturing' : 'Backfilling')
         }}{{ source.backfill_posts
               ? ` · ${source.backfill_posts} posts`
               : (source.backfill_chunks ? ` (${source.backfill_chunks})` : '') }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
-        size="x-small" color="success" variant="tonal" label
+        size="x-small" color="success" variant="flat" label
       >Backfilled</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'stalled'"
-        size="x-small" color="warning" variant="tonal" label
+        size="x-small" color="warning" variant="flat" label
       >Stalled</v-chip>
     </div>
 

frontend/src/components/subscriptions/SourceRow.vue

@@ -72,7 +72,7 @@
            worked, the content just isn't ours. -->
       <v-chip
         v-else-if="source.error_type === 'tier_limited'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
         prepend-icon="mdi-lock-outline"
       >{{ source.tier_gated_count ? `${source.tier_gated_count} gated` : 'No access' }}
         <v-tooltip activator="parent" location="top" max-width="480">
@@ -81,18 +81,18 @@
       </v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'running'"
-        size="x-small" color="info" variant="tonal" label
+        size="x-small" color="info" variant="flat" label
       >{{ source.backfill_bypass_seen ? 'Recovering' : (source.backfill_recapture ? 'Recapturing' : 'Backfilling')
         }}{{ source.backfill_posts
               ? ` · ${source.backfill_posts} posts`
               : (source.backfill_chunks ? ` (${source.backfill_chunks})` : '') }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
-        size="x-small" color="success" variant="tonal" label
+        size="x-small" color="success" variant="flat" label
       >Backfilled</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'stalled'"
-        size="x-small" color="warning" variant="tonal" label
+        size="x-small" color="warning" variant="flat" label
       >Stalled</v-chip>
       <span v-else class="fc-source-row__zero">0</span>
     </td>