feat(feed): per-category any/all tag match, in each combobox's popover footer

The tag 'Match: Any/All' toggle was a single GLOBAL setting that only ever
affected topics, shown as its own row under the Topic widget. Make it
per-category — language, topic, and 'your tags' each get their own independent
any/all — and move it into each filter combobox's popover footer (like
SortControl's direction segment), reclaiming the standalone Match row.

Backend: the feed query already groups selected tags by category; replace the
single tag_mode with per-category tag_mode_language/topic/other params and apply
the conjunctive (HAVING all) branch per category. Mirrored across filtered_query,
feed_summary.passes(), and the /facets drill-down exclusion (kept in lockstep;
equivalence test updated to tag_mode_topic). No schema change.

Frontend: FeedFilters.tagMode -> tagModes {language,topic,other} (pure leaf
lib/api/tagModes with a coerceTagModes migration for the legacy global value);
serialized to the API and the shareable URL per category (legacy ?tagmode=and
still resolves into the topic slot); saved-view blobs migrate on read. Combobox
gains an optional matchMode/onMatchModeChange footer segment, shown once 2+
values are picked; the three tag comboboxes wire it to their category.

Verified: backend feed tests green (12, incl. the count/facets equivalence net);
live, the footer appears at 2+ selections, toggles aria-pressed, serializes
tagmode_topic=and to the URL, and the request carries tag_mode_topic=and (200).
374 vitest, tsc, ruff, eslint (0 err).

frontend/src/components/Sidebar.tsx

@@ -3,7 +3,7 @@ import { useTranslation } from "react-i18next";
 import { keepPreviousData, useQuery } from "@tanstack/react-query";
 import { qk } from "../lib/queryKeys";
 import { Pencil, SlidersHorizontal } from "lucide-react";
-import { api, type FeedFilters, type Tag } from "../lib/api";
+import { api, type FeedFilters, type Tag, type TagCategory } from "../lib/api";
 import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
 import { useDebounced } from "../lib/useDebounced";
 import { clearedFilters, useActiveFilters } from "../lib/useActiveFilters";
@@ -14,7 +14,6 @@ import FilterRail from "./FilterRail";
 import { type PanelItem } from "./PanelGroups";
 import { type MediaSourceKind } from "../lib/mediaSource";
 import ChannelPicker from "./ChannelPicker";
-import SegmentedToggle from "./SegmentedToggle";
 import FilterChipGroup from "./FilterChipGroup";
 import Combobox, { type ComboboxOption } from "./Combobox";
 import { useFeedFilters, useFeedFiltersActions } from "./FeedFiltersProvider";
@@ -97,6 +96,9 @@ export default function Sidebar({
       tags: [...filters.tags.filter((id) => !inList.has(id)), ...next.map(Number)],
     });
   }
+  // Each tag category (language/topic/other) has its OWN any/all match, set from its combobox footer.
+  const setTagMode = (category: TagCategory, mode: "or" | "and") =>
+    setFilters({ ...filters, tagModes: { ...filters.tagModes, [category]: mode } });
 
   // The badge counts exactly what the chip row above the feed shows — same list, so they can't
   // disagree about what's applied.
@@ -200,31 +202,22 @@ export default function Sidebar({
             selected={selectedIn(languages)}
             onChange={(next) => setTagSelection(languages, next)}
             emptyText={t("sidebar.noMatchingTags")}
+            matchMode={filters.tagModes.language}
+            onMatchModeChange={(m) => setTagMode("language", m)}
           />
         );
       }
       case "topic": {
         return (
-          <div className="flex flex-col gap-2">
-            <SegmentedToggle
-              label={t("sidebar.match")}
-              title={t("sidebar.tagModeTooltip")}
-              ariaLabel={t("sidebar.match")}
-              options={[
-                { value: "or", label: t("sidebar.any") },
-                { value: "and", label: t("sidebar.all") },
-              ]}
-              value={filters.tagMode}
-              onChange={(tagMode) => setFilters({ ...filters, tagMode })}
-            />
-            <Combobox
-              label={t("sidebar.widget.topic")}
-              options={visibleChips(topics).map(tagOption)}
-              selected={selectedIn(topics)}
-              onChange={(next) => setTagSelection(topics, next)}
-              emptyText={t("sidebar.noMatchingTags")}
-            />
-          </div>
+          <Combobox
+            label={t("sidebar.widget.topic")}
+            options={visibleChips(topics).map(tagOption)}
+            selected={selectedIn(topics)}
+            onChange={(next) => setTagSelection(topics, next)}
+            emptyText={t("sidebar.noMatchingTags")}
+            matchMode={filters.tagModes.topic}
+            onMatchModeChange={(m) => setTagMode("topic", m)}
+          />
         );
       }
       case "tags": {
@@ -236,6 +229,8 @@ export default function Sidebar({
               selected={selectedIn(userTags)}
               onChange={(next) => setTagSelection(userTags, next)}
               emptyText={t("sidebar.noMatchingTags")}
+              matchMode={filters.tagModes.other}
+              onMatchModeChange={(m) => setTagMode("other", m)}
             />
             <button
               onClick={() => setTagManagerOpen(true)}