Tree view: configurable generation depth (ancestors/descendants + All)

Depth was hardcoded (3 ancestors, 2 descendants). Add a controls row to set
each direction independently — a slider plus a number stepper, with an "All"
toggle per direction — applied around whoever is currently focused.

- ancestor/descendant depth held in state; effective value is a large cap
  when "All" is on (the chart only renders people that exist, so the cap is
  free).
- changes apply to the live chart via setAncestryDepth/setProgenyDepth +
  updateTree without a full rebuild.
- fan mode (ancestors only) takes the ancestor depth via its `generations`
  prop, capped at 8 to avoid the radial layout's 2^n blow-up; its descendants
  control is disabled with a note.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Justin Paul <justin@jpaul.me>

frontend/app/trees/[id]/tree/page.tsx

@@ -46,6 +46,16 @@ export default function TreePage() {
   const [homeId, setHomeId] = useState<string | null>(null);
   const [mode, setMode] = useState<Mode>("landscape");
   const [renderNote, setRenderNote] = useState<string | null>(null);
+  // How many generations to show around the focus, each independently settable
+  // (or "all"). ALL_DEPTH is just a number bigger than any real lineage; the
+  // chart only renders people that exist, so a high cap costs nothing.
+  const [ancDepth, setAncDepth] = useState(3); // ancestors (backwards)
+  const [progDepth, setProgDepth] = useState(2); // descendants (forwards)
+  const [ancAll, setAncAll] = useState(false);
+  const [progAll, setProgAll] = useState(false);
+  const ALL_DEPTH = 100;
+  const effAnc = ancAll ? ALL_DEPTH : ancDepth;
+  const effProg = progAll ? ALL_DEPTH : progDepth;
 
   useEffect(() => {
     let cancelled = false;
@@ -185,9 +195,9 @@ export default function TreePage() {
         chart.setCardHtml().setCardDisplay([["first name", "last name"], ["birthday"]]);
         if (mode === "portrait") chart.setOrientationVertical();
         else chart.setOrientationHorizontal();
-        // Show enough generations that a recenter reveals grandparents + children.
-        chart.setAncestryDepth?.(3);
-        chart.setProgenyDepth?.(2);
+        // Generations to show around the focus (configurable; see depth controls).
+        chart.setAncestryDepth?.(effAnc);
+        chart.setProgenyDepth?.(effProg);
         // Default card click recenters the whole hourglass; sync focus for the
         // "Open profile" link after every (re)build.
         chart.setAfterUpdate?.(() => {
@@ -219,6 +229,15 @@ export default function TreePage() {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [status, mode, people, rels, events]);
 
+  // Apply depth changes to the already-built chart without a full rebuild
+  // (landscape/portrait only; the fan reads its own `generations` prop).
+  useEffect(() => {
+    if (mode === "fan" || !chartRef.current) return;
+    chartRef.current.setAncestryDepth?.(effAnc);
+    chartRef.current.setProgenyDepth?.(effProg);
+    chartRef.current.updateTree?.();
+  }, [effAnc, effProg, mode]);
+
   // Jump the tree (or fan) to a person and rebuild the hourglass around them.
   const goTo = useCallback(
     (id: string) => {
@@ -261,6 +280,68 @@ export default function TreePage() {
     </button>
   );
 
+  // Slider + number stepper + "All" for one generation direction.
+  const DepthControl = ({
+    label,
+    icon,
+    value,
+    all,
+    onValue,
+    onAll,
+    disabled,
+  }: {
+    label: string;
+    icon: string;
+    value: number;
+    all: boolean;
+    onValue: (v: number) => void;
+    onAll: (b: boolean) => void;
+    disabled?: boolean;
+  }) => (
+    <div className={`flex items-center gap-2 ${disabled ? "opacity-40" : ""}`}>
+      <span className="flex w-24 items-center gap-1 text-xs text-[var(--muted)]">
+        <span aria-hidden>{icon}</span> {label}
+      </span>
+      <input
+        type="range"
+        min={0}
+        max={12}
+        step={1}
+        value={all ? 12 : value}
+        disabled={disabled || all}
+        onChange={(e) => onValue(Number(e.target.value))}
+        className="w-28 accent-bronze"
+        aria-label={`${label} generations`}
+      />
+      {all ? (
+        <span className="w-10 text-center text-sm font-medium text-bronze">All</span>
+      ) : (
+        <input
+          type="number"
+          min={0}
+          max={99}
+          value={value}
+          disabled={disabled}
+          onChange={(e) => onValue(Math.max(0, Math.min(99, Number(e.target.value) || 0)))}
+          className="h-7 w-12 rounded-md border border-[var(--border)] bg-[var(--surface)] px-1 text-center text-sm"
+        />
+      )}
+      <button
+        type="button"
+        disabled={disabled}
+        onClick={() => onAll(!all)}
+        title={`Show all ${label.toLowerCase()}`}
+        className={`rounded-md px-2 py-1 text-xs transition-colors ${
+          all
+            ? "bg-bronze text-paper"
+            : "border border-[var(--border)] text-[var(--muted)] hover:text-[var(--foreground)]"
+        }`}
+      >
+        All
+      </button>
+    </div>
+  );
+
   return (
     <div className="space-y-4">
       <div className="flex flex-wrap items-center justify-between gap-3">
@@ -319,6 +400,38 @@ export default function TreePage() {
         </div>
       </div>
 
+      {status === "ready" && (
+        <div className="flex flex-wrap items-center gap-x-6 gap-y-2 rounded-lg border border-[var(--border)] bg-[var(--surface)] px-4 py-2.5">
+          <span className="text-sm font-medium">Generations</span>
+          <DepthControl
+            label="Ancestors"
+            icon="↑"
+            value={ancDepth}
+            all={ancAll}
+            onValue={(v) => {
+              setAncAll(false);
+              setAncDepth(v);
+            }}
+            onAll={setAncAll}
+          />
+          <DepthControl
+            label="Descendants"
+            icon="↓"
+            value={progDepth}
+            all={progAll}
+            onValue={(v) => {
+              setProgAll(false);
+              setProgDepth(v);
+            }}
+            onAll={setProgAll}
+            disabled={mode === "fan"}
+          />
+          {mode === "fan" && (
+            <span className="text-xs text-[var(--muted)]">Fan shows ancestors only.</span>
+          )}
+        </div>
+      )}
+
       {status === "empty" && (
         <p className="text-[var(--muted)]">No people yet — add some under People, or import a GEDCOM.</p>
       )}
@@ -338,6 +451,7 @@ export default function TreePage() {
             nameOf={nameOf}
             yearOf={yearOf}
             onSelect={setFocusId}
+            generations={Math.min(effAnc, 8)}
           />
         </div>
       ) : (