feat: review queue polish (pace, sort, type filter), drop unused phase-detection UI

Review Queue: show pace alongside distance/duration/HR, sort by activity
date (most recent first) instead of classification timestamp, and add a
filter by workout kind with a special "Unsorted" option for runs where
the rule engine found zero candidates at all (distinct from ambiguous
multi-candidate runs).

Profile: remove the phase-detection warm-up/cool-down section from the
UI -- not used by anything yet (phase segmentation is future work) and
was adding noise. The underlying fields are untouched so no data is lost
and the settings screen still round-trips them on save.

frontend/src/pages/Profile.tsx

@@ -146,36 +146,6 @@ export function Profile() {
         ))}
       </fieldset>
 
-      <fieldset className="kind-editor">
-        <legend>Phase detection (warm-up / cool-down minutes)</legend>
-        {(
-          [
-            ["Easy", "EasyWarmupMinutes", "EasyCooldownMinutes"],
-            ["Long", "LongWarmupMinutes", "LongCooldownMinutes"],
-            ["Tempo", "TempoWarmupMinutes", "TempoCooldownMinutes"],
-            ["Threshold 30'", "Threshold30WarmupMinutes", "Threshold30CooldownMinutes"],
-            ["Threshold 60'", "Threshold60WarmupMinutes", "Threshold60CooldownMinutes"],
-            ["MAS Test", "MASTestWarmupMinutes", "MASTestCooldownMinutes"],
-          ] as const
-        ).map(([label, warmupKey, cooldownKey]) => (
-          <div key={label} className="controls">
-            <NumberField
-              label={`${label} warm-up`}
-              value={profile[warmupKey]}
-              onChange={(v) => set(warmupKey, v)}
-            />
-            <NumberField
-              label={`${label} cool-down`}
-              value={profile[cooldownKey]}
-              onChange={(v) => set(cooldownKey, v)}
-            />
-          </div>
-        ))}
-        <p className="empty-state">
-          Interval workouts detect warm-up/cool-down from lap data directly and don't use these settings.
-        </p>
-      </fieldset>
-
       <button onClick={save}>Save</button>
     </div>
   );

frontend/src/pages/ReviewQueue.tsx

@@ -1,7 +1,9 @@
-import { useEffect, useState } from "react";
+import { useEffect, useMemo, useState } from "react";
 import { api } from "../api/client";
 import type { ReviewQueueItem, ScoredKind, WorkoutKind } from "../types/api";
 
+const UNSORTED = "__unsorted__";
+
 function candidates(item: ReviewQueueItem): ScoredKind[] {
   try {
     return JSON.parse(item.CandidateKindsJSON) as ScoredKind[];
@@ -10,9 +12,18 @@ function candidates(item: ReviewQueueItem): ScoredKind[] {
   }
 }
 
+function formatPace(avgSpeedMps: number | null): string | null {
+  if (avgSpeedMps == null || avgSpeedMps <= 0) return null;
+  const secPerKm = 1000 / avgSpeedMps;
+  const m = Math.floor(secPerKm / 60);
+  const s = Math.round(secPerKm % 60);
+  return `${m}:${s.toString().padStart(2, "0")}/km`;
+}
+
 export function ReviewQueue() {
   const [items, setItems] = useState<ReviewQueueItem[]>([]);
   const [kinds, setKinds] = useState<WorkoutKind[]>([]);
+  const [filterKindId, setFilterKindId] = useState<string>("");
   const [error, setError] = useState<string | null>(null);
   const [resolvingId, setResolvingId] = useState<number | null>(null);
 
@@ -39,17 +50,46 @@ export function ReviewQueue() {
     }
   }
 
+  const filteredItems = useMemo(() => {
+    if (filterKindId === "") return items;
+    if (filterKindId === UNSORTED) {
+      return items.filter((item) => candidates(item).length === 0);
+    }
+    const id = Number(filterKindId);
+    return items.filter((item) => candidates(item).some((c) => c.workout_kind_id === id));
+  }, [items, filterKindId]);
+
   return (
     <div className="page">
       <h2>Review Queue</h2>
       {error && <p className="error">{error}</p>}
 
+      {items.length > 0 && (
+        <div className="controls">
+          <label>
+            Filter
+            <select value={filterKindId} onChange={(e) => setFilterKindId(e.target.value)}>
+              <option value="">All ({items.length})</option>
+              <option value={UNSORTED}>Unsorted (no candidates)</option>
+              {kinds.map((k) => (
+                <option key={k.ID} value={k.ID}>
+                  {k.Name}
+                </option>
+              ))}
+            </select>
+          </label>
+        </div>
+      )}
+
       {items.length === 0 ? (
         <p className="empty-state">Nothing needs review right now.</p>
+      ) : filteredItems.length === 0 ? (
+        <p className="empty-state">No runs match this filter.</p>
       ) : (
         <ul className="review-list">
-          {items.map((item) => {
+          {filteredItems.map((item) => {
             const scored = candidates(item);
+            const pace = formatPace(item.activity.AvgSpeedMps);
             return (
               <li key={item.ActivityID} className="review-item">
                 <div className="review-item-header">
@@ -59,6 +99,7 @@ export function ReviewQueue() {
                 <div className="review-item-stats">
                   <span>{(item.activity.DistanceMeters / 1000).toFixed(2)} km</span>
                   <span>{Math.round(item.activity.DurationSeconds / 60)} min</span>
+                  {pace && <span>{pace}</span>}
                   {item.activity.AvgHR != null && <span>{Math.round(item.activity.AvgHR)} bpm avg</span>}
                 </div>