Case archive/restore with Paperclip sync

Adds a comprehensive archive flow for closed cases — separate /archive
screen in the UI, archive/restore actions on the case detail page, and
automatic two-way sync with Paperclip.

Backend (web/app.py + mcp-server/services/db.py):
- New SCHEMA_V6 migration: cases.archived_at TIMESTAMPTZ + partial index
- list_cases gains include_archived/archived_only flags; default excludes
  archived rows so the main /api/cases list hides closed cases
- archive_case / restore_case helpers in db.py
- POST /api/cases/{n}/archive sets archived_at and calls
  pc_archive_project (sets Paperclip projects.archived_at via direct DB)
- POST /api/cases/{n}/restore clears archived_at and calls
  pc_restore_project (clears Paperclip archived_at)
- archive_project / restore_project in paperclip_client.py — name-based
  match consistent with create_project's lookup

Frontend (web-ui):
- cases.ts: scope param ("active"|"archived"|"all") on useCases;
  useArchiveCase / useRestoreCase mutations
- /archive page (new): table of archived cases with restore button +
  search, sort, empty state matching the editorial aesthetic of /
- case-archive-action.tsx: button on case detail header. Active case →
  confirm dialog → archive. Archived case → restore (no confirm).
  Toast announces both legal-ai and Paperclip outcomes (synced, not
  found in pc, error)
- case-header shows "בארכיון" badge when archived_at is set
- Nav: ארכיון link added to AppShell after בית

Tested end-to-end against the live DB:
- 1130-25 archive → list_cases(include_archived=False) excludes it,
  list_cases(archived_only=True) includes it, restore reverses
- pc archive/restore on 1194-25 verified via direct DB lookup
- TypeScript compiles clean

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/paperclip_client.py

@@ -138,6 +138,59 @@ async def create_project(
         await conn.close()
 
 
+async def archive_project(case_number: str) -> dict:
+    """Set archived_at on the Paperclip project matching this case number.
+
+    The project is identified by `name LIKE '%{case_number}%'` (consistent with
+    `create_project`'s lookup). Idempotent — if already archived, returns the
+    existing timestamp.
+    """
+    conn = await asyncpg.connect(PAPERCLIP_DB_URL)
+    try:
+        row = await conn.fetchrow(
+            """UPDATE projects
+               SET archived_at = COALESCE(archived_at, now()),
+                   updated_at = now()
+               WHERE name LIKE $1 RETURNING id, name, archived_at""",
+            f"%{case_number}%",
+        )
+        if not row:
+            return {"status": "not_found", "case_number": case_number}
+        return {
+            "status": "archived",
+            "project_id": str(row["id"]),
+            "name": row["name"],
+            "archived_at": row["archived_at"].isoformat() if row["archived_at"] else None,
+        }
+    finally:
+        await conn.close()
+
+
+async def restore_project(case_number: str) -> dict:
+    """Clear archived_at on the Paperclip project matching this case number.
+
+    Idempotent — if already active, returns success without changes.
+    """
+    conn = await asyncpg.connect(PAPERCLIP_DB_URL)
+    try:
+        row = await conn.fetchrow(
+            """UPDATE projects
+               SET archived_at = NULL,
+                   updated_at = now()
+               WHERE name LIKE $1 RETURNING id, name""",
+            f"%{case_number}%",
+        )
+        if not row:
+            return {"status": "not_found", "case_number": case_number}
+        return {
+            "status": "restored",
+            "project_id": str(row["id"]),
+            "name": row["name"],
+        }
+    finally:
+        await conn.close()
+
+
 async def _create_issue(
     conn: asyncpg.Connection,
     company_id: str,