feat(case-ui): merge /compose editor into case tabs (X17 #3)

Folds the standalone /compose decision-editor route into the main case page so
there is no more "sub-page" (mockup 18f), with the final 6-tab workflow order:
סקירה · טיעונים ועמדות · אימות פסיקה · ההחלטה · טיוטות והערות · סוכנים.

- New PositionsPanel — the chair's editing surface (threshold claims + issues
  SubsectionCards + ChairEditor + background prose + case precedents + finish
  rail), extracted verbatim from the former /compose "עמדות וטענות" tab. Drops
  only the doc-strip (the overview DocumentsPanel is the sole owner — no dup).
- "טיעונים ועמדות" tab = PositionsPanel above + the aggregated by-party
  LegalArgumentsPanel in a collapsible below.
- "אימות פסיקה" promoted to its own top-level tab (CitationVerificationPanel,
  was /compose tab 3); placed BEFORE "ההחלטה" — verify citations, then write
  (INV-AH: the writer cites only verified precedents).
- "ההחלטה" stays the single 12-block editor (DecisionBlocksPanel) — no longer
  duplicated between /compose and the case page.
- Tabs are now controlled; the "פתח עורך החלטה" CTA switches to the ההחלטה tab
  instead of navigating to the deleted route.
- /compose route deleted; header-context /compose special-case removed.

No duplication remains (G2): blocks editor single, docs single (overview),
citation-verify single. Design-gate: mockup 18f approved in Claude Design X17.
tsc --noEmit + eslint clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/app/cases/[caseNumber]/page.tsx

@@ -1,10 +1,13 @@
 "use client";
 
-import { use } from "react";
+import { use, useState } from "react";
 import Link from "next/link";
 import { AppShell } from "@/components/app-shell";
 import { Card, CardContent } from "@/components/ui/card";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
+import {
+  Accordion, AccordionContent, AccordionItem, AccordionTrigger,
+} from "@/components/ui/accordion";
 import { Button } from "@/components/ui/button";
 import { Skeleton } from "@/components/ui/skeleton";
 import { CaseHeader } from "@/components/cases/case-header";
@@ -13,13 +16,15 @@ import { DocumentsPanel } from "@/components/cases/documents-panel";
 import { DraftsPanel } from "@/components/cases/drafts-panel";
 import { DecisionBlocksPanel } from "@/components/cases/decision-blocks-panel";
 import { LegalArgumentsPanel } from "@/components/cases/legal-arguments-panel";
+import { PositionsPanel } from "@/components/cases/positions-panel";
+import { CitationVerificationPanel } from "@/components/compose/citation-verification-panel";
 import { AgentActivityFeed } from "@/components/cases/agent-activity-feed";
 import { AgentActivityPreview } from "@/components/cases/agent-activity-preview";
 import { UploadSheet } from "@/components/documents/upload-sheet";
 import { useCase, useStartWorkflow } from "@/lib/api/cases";
 import { toast } from "sonner";
 import {
-  Play, Loader2, LayoutGrid, Scale, FileText, MessageSquare, Users,
+  Play, Loader2, LayoutGrid, Scale, BadgeCheck, FileText, MessageSquare, Users,
   type LucideIcon,
 } from "lucide-react";
 
@@ -33,6 +38,7 @@ export default function CaseDetailPage({
   params: Promise<{ caseNumber: string }>;
 }) {
   const { caseNumber } = use(params);
+  const [tab, setTab] = useState("overview");
   const { data, isPending, error, refetch } = useCase(caseNumber);
   const startWorkflow = useStartWorkflow(caseNumber);
   const canStartWorkflow = data?.status === "new" || data?.status === "documents_ready";
@@ -62,9 +68,12 @@ export default function CaseDetailPage({
     );
   }
 
+  // Workflow order (X17): intake → arguments+positions → verify citations →
+  // write decision → drafts/final → agents (monitoring).
   const tabDefs: [string, string, LucideIcon][] = [
     ["overview", "סקירה", LayoutGrid],
-    ["arguments", "טיעונים", Scale],
+    ["arguments", "טיעונים ועמדות", Scale],
+    ["verify", "אימות פסיקה", BadgeCheck],
     ["decision", "ההחלטה", FileText],
     ["drafts", "טיוטות והערות", MessageSquare],
     ["agents", "סוכנים", Users],
@@ -93,8 +102,11 @@ export default function CaseDetailPage({
     <>
       {data && <CaseEditDialog data={data} />}
       <UploadSheet caseNumber={caseNumber} />
-      <Button asChild className="bg-gold text-white hover:bg-gold-deep border-transparent">
-        <Link href={`/cases/${caseNumber}/compose`}>פתח עורך החלטה</Link>
+      <Button
+        className="bg-gold text-white hover:bg-gold-deep border-transparent"
+        onClick={() => setTab("decision")}
+      >
+        פתח עורך החלטה
       </Button>
       {canStartWorkflow && (
         <Button
@@ -121,7 +133,7 @@ export default function CaseDetailPage({
 
   return (
     <AppShell>
-      <Tabs defaultValue="overview" dir="rtl">
+      <Tabs value={tab} onValueChange={setTab} dir="rtl">
         {/* parchment band — header (title/chips/parties/actions) + tab strip */}
         {isPending ? (
           <div className="-mx-10 -mt-10 mb-2 bg-parchment border-b border-rule px-10 pt-6 pb-4 space-y-3">
@@ -144,10 +156,43 @@ export default function CaseDetailPage({
             </div>
           </TabsContent>
 
-          <TabsContent value="arguments" className="mt-0">
+          {/* טיעונים ועמדות — chair positions (editing) over the analyst's
+              issues, with the aggregated by-party arguments collapsible below
+              (merged from the deleted /compose editor, mockup 18f). */}
+          <TabsContent value="arguments" className="mt-0 space-y-4">
             <Card className="bg-surface border-rule shadow-sm">
               <CardContent className="px-6 py-5">
-                <LegalArgumentsPanel caseNumber={caseNumber} />
+                <PositionsPanel caseNumber={caseNumber} />
+              </CardContent>
+            </Card>
+            <Accordion type="single" collapsible>
+              <AccordionItem
+                value="byparty"
+                className="overflow-hidden rounded-xl border border-rule bg-surface shadow-sm"
+              >
+                <AccordionTrigger className="px-6 py-4 hover:no-underline">
+                  <span className="flex flex-1 flex-col items-start">
+                    <span className="text-navy text-[0.95rem] font-bold">
+                      טיעונים מאוגדים לפי צד
+                    </span>
+                    <span className="text-ink-muted text-[0.78rem]">
+                      תצוגה מסונתזת של הטענות הגולמיות, מקובצת לפי צד וקדימות
+                    </span>
+                  </span>
+                </AccordionTrigger>
+                <AccordionContent className="px-6 pb-5 pt-0">
+                  <LegalArgumentsPanel caseNumber={caseNumber} />
+                </AccordionContent>
+              </AccordionItem>
+            </Accordion>
+          </TabsContent>
+
+          {/* אימות פסיקה — per-argument supporting-precedent verify gate (#154),
+              relocated from the deleted /compose editor to a top-level tab. */}
+          <TabsContent value="verify" className="mt-0">
+            <Card className="bg-surface border-rule shadow-sm">
+              <CardContent className="px-6 py-5">
+                <CitationVerificationPanel caseNumber={caseNumber} />
               </CardContent>
             </Card>
           </TabsContent>