Close DV-01–04,07,09,13,14: unify operator-deck UX in server/web.

Standardize neon cyan on #00e8f5, wire SacredPageHeader across Builds/Path Tracer/LOTL, dedupe Pages.css, align Path Tracer chrome, drop dead wealth-deck CSS, add prefers-color-scheme shell + HelpTip, sidebar version from package.json build inject, and Vitest CSS regression guards.

server/internal/db/pathtrace_sessions_test.go

@@ -0,0 +1,36 @@
+package db
+
+import (
+	"testing"
+	"time"
+)
+
+func TestPathTraceSessionPersistenceAndSweep(t *testing.T) {
+	d := openTestDB(t)
+
+	fresh := []byte(`{"id":"sess-fresh","ready":true}`)
+	stale := []byte(`{"id":"sess-stale","ready":false}`)
+
+	if err := d.UpsertPathTraceSession("sess-fresh", time.Now().Add(-30*time.Minute), fresh); err != nil {
+		t.Fatal(err)
+	}
+	if err := d.UpsertPathTraceSession("sess-stale", time.Now().Add(-3*time.Hour), stale); err != nil {
+		t.Fatal(err)
+	}
+
+	deleted, err := d.DeleteExpiredPathTraceSessions(time.Now().Add(-2 * time.Hour))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if deleted != 1 {
+		t.Fatalf("expected 1 stale row deleted, got %d", deleted)
+	}
+
+	rows, err := d.ListPathTraceSessions()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rows) != 1 || rows[0].ID != "sess-fresh" {
+		t.Fatalf("expected fresh session only, got %+v", rows)
+	}
+}