sidebar polish: tighter chevron + '+' drops to Research line

- Dashboard chevron: 24x24 → 22x22, top:10 right:8 → top:4 right:4
  so it sits in the true corner of the panel.
- ResearchList header: alignItems flex-start → flex-end so the '+'
  button lands on the 'Research' title baseline instead of hugging
  the 'N TOPICS' caption line. Reserved 34px right padding on the
  header so the '+' clears the corner chevron.

frontend/src/components/dashboard/Dashboard.tsx

@@ -692,7 +692,7 @@ export function Dashboard({ user, orgs, claws }: { user?: { display_name?: strin
             onClick={toggleSidebar}
             title="Collapse sidebar"
             aria-label="Collapse sidebar"
-            style={{ position: "absolute", top: 10, right: 8, zIndex: 5, width: 24, height: 24, borderRadius: 6, border: "1px solid rgba(255,255,255,.12)", background: "rgba(0,0,0,.35)", color: "#cfcfd5", cursor: "pointer", display: "inline-flex", alignItems: "center", justifyContent: "center" }}
+            style={{ position: "absolute", top: 4, right: 4, zIndex: 5, width: 22, height: 22, borderRadius: 6, border: "1px solid rgba(255,255,255,.1)", background: "rgba(0,0,0,.4)", color: "#cfcfd5", cursor: "pointer", display: "inline-flex", alignItems: "center", justifyContent: "center" }}
           >
             <PanelLeftClose aria-hidden size={13} />
           </button>

frontend/src/components/dashboard/ResearchList.tsx

@@ -123,10 +123,12 @@ export function ResearchList({
     <>
       <div
         style={{
-          padding: "16px 16px 12px",
+          // right padding leaves clear space for the Dashboard's
+          // collapse chevron pinned top-right of this column.
+          padding: "16px 34px 12px 16px",
           borderBottom: "1px solid rgba(255,255,255,.06)",
           display: "flex",
-          alignItems: "flex-start",
+          alignItems: "flex-end",
           gap: 8,
         }}
       >