Precedent attachment UI in the compose screen

Surface the new POST/GET/DELETE /api/cases/{n}/precedents endpoints
in the compose screen as two insertion points:

1. A new case-level card "פסיקה כללית לדיון" at the top of the
   main column, for precedents that support the discussion intro
   rather than a specific threshold_claim / issue.
2. An inline "פסיקה תומכת" section inside each SubsectionCard,
   below the ChairEditor.

Both insertion points render a `<PrecedentsSection>` which shows a
list of `<PrecedentCard>` (citation + blockquote + optional chair
note + 📄 chip if a PDF was archived) followed by a `<PrecedentAttacher>`
popover trigger.

The Attacher is a Popover with cross-case typeahead: typing 2+
characters into the citation field hits /api/precedents/search and
shows distinct library matches; picking one prefills quote + chair
note but leaves them editable so customizing the quote for this
case doesn't mutate the library. An optional PDF/DOCX/DOC file can
be attached — it uploads first via POST .../upload-pdf and the
returned document_id is passed into the precedent create call.

The parent compose page issues a single useCasePrecedents query
and partitions the result by section_id into a Map so each
SubsectionCard renders its own slice without re-fetching.

shadcn Popover installed as a new primitive. sonner toasts wired
for success/error in both attach and delete flows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -7,8 +7,10 @@ import { Card, CardContent } from "@/components/ui/card";
 import { Button } from "@/components/ui/button";
 import { Skeleton } from "@/components/ui/skeleton";
 import { SubsectionCard } from "@/components/compose/subsection-card";
+import { PrecedentsSection } from "@/components/compose/precedents-section";
 import { useCase } from "@/lib/api/cases";
 import { useResearchAnalysis } from "@/lib/api/research";
+import { useCasePrecedents } from "@/lib/api/precedents";
 
 function ProseSection({ title, content }: { title: string; content?: string }) {
   if (!content?.trim()) return null;
@@ -32,6 +34,21 @@ export default function ComposePage({
   const { caseNumber } = use(params);
   const caseQuery = useCase(caseNumber);
   const analysis = useResearchAnalysis(caseNumber);
+  const precedentsQuery = useCasePrecedents(caseNumber);
+
+  /* Partition the flat list into scopes so each child renders its own slice
+   * without re-fetching. Done once at the page level. */
+  const allPrecedents = precedentsQuery.data ?? [];
+  const caseLevelPrecedents = allPrecedents.filter((p) => p.section_id === null);
+  const precedentsBySection = new Map<string, typeof allPrecedents>();
+  for (const p of allPrecedents) {
+    if (p.section_id) {
+      const existing = precedentsBySection.get(p.section_id) ?? [];
+      existing.push(p);
+      precedentsBySection.set(p.section_id, existing);
+    }
+  }
+  const practiceArea = caseQuery.data?.practice_area ?? null;
 
   const isNotFound =
     analysis.error instanceof Error &&
@@ -101,6 +118,23 @@ export default function ComposePage({
           <div className="grid gap-6 lg:grid-cols-[1fr_320px]">
             {/* Main editable column */}
             <div className="space-y-6">
+              {/* Case-level general precedents */}
+              <Card className="bg-surface border-rule shadow-sm">
+                <CardContent className="px-6 py-5">
+                  <h2 className="text-navy text-xl mb-1">פסיקה כללית לדיון</h2>
+                  <p className="text-[0.78rem] text-ink-muted mb-4">
+                    ציטוטים התומכים בעמדה באופן רוחבי — ישולבו בפתיחת בלוק י (דיון).
+                  </p>
+                  <PrecedentsSection
+                    caseNumber={caseNumber}
+                    sectionId={null}
+                    precedents={caseLevelPrecedents}
+                    practiceArea={practiceArea}
+                    emptyHelperText="עדיין לא צורפה פסיקה כללית לתיק"
+                  />
+                </CardContent>
+              </Card>
+
               {/* Threshold claims */}
               {analysis.data.threshold_claims &&
                 analysis.data.threshold_claims.length > 0 && (
@@ -118,6 +152,8 @@ export default function ComposePage({
                           caseNumber={caseNumber}
                           item={tc}
                           defaultOpen={i === 0}
+                          precedents={precedentsBySection.get(tc.id) ?? []}
+                          practiceArea={practiceArea}
                         />
                       ))}
                     </div>
@@ -139,6 +175,8 @@ export default function ComposePage({
                         key={iss.id}
                         caseNumber={caseNumber}
                         item={iss}
+                        precedents={precedentsBySection.get(iss.id) ?? []}
+                        practiceArea={practiceArea}
                       />
                     ))}
                   </div>