fix(filter-builder): OR-aware suggest constraints (user correction)

The previous fix was too blunt: under OR it sent NO constraint tree at
all, so "library = ebooks" stopped narrowing the author menu the
moment an OR-connected author rule appeared. The user spec is subtler:

  library = ebooks AND (author = Lewis Carroll OR author = ?)
  → the menu shows EBOOK authors, with Lewis Carroll OFF the list.

suggestTree now walks root → edited rule and builds one conjunctive
chain:

- ALL-group siblings stay (AND narrows: the ebook scope persists);
- ANY-group siblings drop — they are independent alternatives under
  OR and must not narrow;
- EXCEPT a same-field ANY sibling, whose picked values NEGATE into
  the chain (contains → not_contains, is → is_not, in → not_in): the
  picked value leaves the menu, everything else in scope stays;
- an ALREADY-NEGATED sibling picks nothing to take off, so it drops
  rather than flipping positive (a positive flip would narrow);
- a field without a negation twin falls back to dropping;
- incomplete rules never constrain (not filters yet), and the edited
  rule itself never constrains its own menu.

Pins: the user's exact tree (ebook scope kept + Lewis Carroll negated
off), the root-OR variant (different-field sibling drops, same-field
negates), the twinless fallback, plus the existing AND/OR cases —
34 filter-builder vitest cases green, container filter slice green
(TestFilterSuggestionsUnderRules unaffected: the server contract is
unchanged, only which qf the client composes).

web/src/filter_builder.test.ts

@@ -251,7 +251,10 @@ const builderFields = [
     valueKind: "text" as const,
     defaultOp: "contains",
     suggest: true,
-    ops: [{ key: "contains", label: "contains", arity: "many" }],
+    ops: [
+      { key: "contains", label: "contains", arity: "many" },
+      { key: "not_contains", label: "does not contain", arity: "many" },
+    ],
   },
 ];
 
@@ -291,6 +294,63 @@ describe("mode-aware value suggestions", () => {
     expect(decodeURIComponent(captured.replace(/\+/g, " "))).toContain("Lewis Carroll");
   });
 
+  it("user spec: AND scope stays, the OR sibling's pick comes off the list", async () => {
+    const c = filterBuilderData();
+    c.filterTree = {
+      mode: "all",
+      children: [
+        { field: "library", op: "in", values: ["lib-ebooks"] },
+        {
+          mode: "any" as const,
+          children: [
+            { field: "author", op: "contains", values: ["Lewis Carroll"] },
+            { field: "author", op: "contains", values: [""] },
+          ],
+        },
+      ],
+    };
+    await c.fetchSuggestions("1-1", [1, 1], { field: "author", op: "contains", values: [""] });
+    expect(captured).toContain("qf=");
+    const qf = decodeURIComponent(captured.split("qf=")[1]!.split("&")[0]!.replace(/\+/g, " "));
+    // the ebook scope still narrows…
+    expect(qf).toContain('"field":"library"');
+    expect(qf).toContain("lib-ebooks");
+    // …and Lewis Carroll is REMOVED, not the only option
+    expect(qf).toContain("not_contains");
+    expect(qf).toContain("Lewis Carroll");
+  });
+
+  it("root OR: a different-field sibling drops, a same-field pick negates", async () => {
+    const c = filterBuilderData();
+    c.filterTree = {
+      mode: "any",
+      children: [
+        { field: "library", op: "in", values: ["lib-ebooks"] },
+        { field: "author", op: "contains", values: ["Lewis Carroll"] },
+        { field: "author", op: "contains", values: [""] },
+      ],
+    };
+    await c.fetchSuggestions("2", [2], { field: "author", op: "contains", values: [""] });
+    expect(captured).toContain("qf=");
+    const qf = decodeURIComponent(captured.split("qf=")[1]!.split("&")[0]!.replace(/\+/g, " "));
+    expect(qf).not.toContain("library");
+    expect(qf).toContain("not_contains");
+    expect(qf).toContain("Lewis Carroll");
+  });
+
+  it("a same-field OR sibling without a negation twin just drops", async () => {
+    const c = filterBuilderData();
+    c.filterTree = {
+      mode: "any",
+      children: [
+        { field: "library", op: "in", values: ["lib-1"] },
+        { field: "library", op: "in", values: [""] },
+      ],
+    };
+    await c.fetchSuggestions("1", [1], { field: "library", op: "in", values: [""] });
+    expect(captured).not.toContain("qf=");
+  });
+
   it("sends NO sibling tree under OR — the menu browses the scope", async () => {
     const c = filterBuilderData();
     c.filterTree = {

web/src/filter_builder.ts

@@ -273,6 +273,80 @@ export function pruneIncomplete(
   return out;
 }
 
+// completeRuleValues — the completeness test from pruneIncomplete: a
+// value-taking rule is a filter only with trimmed, non-empty values
+// (two-arity needs both). Null = not a filter yet.
+function completeRuleValues(rule: FilterRuleState): string[] | null {
+  const arity = wireOps[rule.op]?.arity ?? "many";
+  if (arity === "none") return [];
+  const vals = (rule.values ?? []).map((v) => (v ?? "").trim());
+  const kept = vals.filter((v) => v !== "");
+  if (kept.length === 0) return null;
+  if (arity === "two" && kept.length < 2) return null;
+  return arity === "two" ? vals : [kept.join(",")];
+}
+
+// negateRule — a same-field OR sibling's negated twin (contains ↔
+// not_contains, is ↔ is_not, in ↔ not_in): the sibling's picked values
+// come OFF the menu while every other value stays ("we've selected
+// Lewis Carroll — remove him, show the rest of the ebook authors").
+// An ALREADY-NEGATED sibling picks nothing, so it drops instead of
+// flipping positive (a positive flip would narrow, not widen). Null =
+// no twin (or nothing picked): the sibling just drops.
+export function negateRule(rule: FilterRuleState): FilterRuleState | null {
+  if (rule.op.startsWith("not_")) return null;
+  const twin = opsForField(rule.field).find((o) => o.key === `not_${rule.op}`);
+  if (!twin) return null;
+  const vals = completeRuleValues(rule);
+  if (vals === null) return null;
+  return { field: rule.field, op: twin.key, values: vals };
+}
+
+// suggestTree — the constraint tree for one rule's value menu. The
+// edited rule's own constraint is gone; walking root → edited rule:
+// • ALL-group siblings stay (AND narrows candidates: "library =
+//   ebooks" keeps the menu to ebook authors);
+// • ANY-group siblings are independent alternatives — they drop,
+//   EXCEPT a same-field sibling, whose picked values NEGATE into the
+//   chain (2026-10-31 user spec: OR must keep the ebook scope, take
+//   the already-picked author off the list, and offer the rest);
+// • incomplete rules never constrain (they are not filters yet).
+// The kept constraints are conjunctive, so the result is one ALL
+// chain; null when nothing constrains (the caller sends no qf).
+export function suggestTree(
+  group: FilterGroupState,
+  path: number[],
+  fieldKey: string,
+): FilterGroupState | null {
+  if (path.length === 0) return null;
+  const onPath = group.children[path[0]];
+  if (!onPath) return null;
+  const children: (FilterRuleState | FilterGroupState)[] = [];
+  group.children.forEach((child, idx) => {
+    if (idx === path[0]) return;
+    if (group.mode === "any") {
+      if (isRule(child) && child.field === fieldKey) {
+        const neg = negateRule(child);
+        if (neg) children.push(neg);
+      }
+      return; // OR siblings never narrow the menu
+    }
+    if (isRule(child)) {
+      const vals = completeRuleValues(child);
+      if (vals !== null) children.push({ field: child.field, op: child.op, values: vals });
+      return;
+    }
+    const pruned = pruneIncomplete(child, null);
+    if (pruned && pruned.children.length > 0) children.push(pruned);
+  });
+  if (path.length > 1 && !isRule(onPath)) {
+    const nested = suggestTree(onPath, path.slice(1), fieldKey);
+    if (nested && nested.children.length > 0) children.push(nested);
+  }
+  if (children.length === 0) return null;
+  return { mode: "all", children };
+}
+
 // ─── row projection (flat rendering of the nested tree) ─────────────
 
 interface BuilderRow {
@@ -634,22 +708,6 @@ export function filterBuilderData() {
       return FIELD_BY_KEY.get(node.field)?.valueKind === "id";
     },
 
-    // pathUnderAll — is every group from the root down to the edited
-    // rule's parent an AND ("all") group? Under any OR on the path the
-    // siblings cannot constrain the rule being edited.
-    pathUnderAll(path: number[]): boolean {
-      if (this.filterTree.mode !== "all") return false;
-      let node: FilterRuleState | FilterGroupState = this.filterTree;
-      for (let i = 0; i < path.length - 1; i++) {
-        if (isRule(node)) return false;
-        const child = (node as FilterGroupState).children[path[i]];
-        if (!child || isRule(child)) return false;
-        node = child;
-        if (node.mode !== "all") return false;
-      }
-      return true;
-    },
-
     // valueCellText — what the value INPUT displays. Id-kind rules keep
     // the ids in rule.values (the clause matches ids); the cell shows
     // their LABELS, or the name text being typed.
@@ -790,16 +848,12 @@ export function filterBuilderData() {
       this.suggestions[rowKey] = [];
       this.suggestionsLoading = rowKey;
       this.suggestionsOpen = rowKey;
-      // Symmetry: the tree sent EXCLUDES the rule being edited — the
+      // The menu is computed under the suggest-constraint tree: AND
-      // menu is computed under every OTHER COMPLETED rule (incomplete
+      // siblings keep narrowing, OR siblings drop (a same-field pick
-      // rules are not filters; sending them would be a 400). Under an
+      // negates in, taking its value off the list), and the edited
-      // OR connective on the edited rule's path (root mode "any" or an
+      // rule itself never constrains. Null = nothing constrains: no
-      // "any" ancestor group), siblings are INDEPENDENT alternatives —
+      // qf rides (an empty group is a server-side 400).
-      // a new rule's candidates must not be narrowed by them — so no
+      const others = suggestTree(this.filterTree, path, rule.field);
-      // tree rides at all (2026-10-31 user report: with "Author
-      // contains Lewis Carroll" present, flipping to OR still starved
-      // the author menu down to Lewis Carroll).
-      const others = this.pathUnderAll(path) ? this.completedTree(path) : null;
       const params = new URLSearchParams();
       params.set(rule.field, typed || " ");
       if (others) params.set("qf", JSON.stringify(others));