feat: add server-side session filtering with input bytes and human score

Replace client-side session table filtering with server-side filtering
via a new /fragments/recent-sessions htmx endpoint. Add InputBytes column
to session tables, Human score > 0 checkbox filter, and Sort by Input
Bytes option to help identify sessions with actual shell interaction.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/web/templates.go

@@ -56,6 +56,20 @@ func templateFuncMap() template.FuncMap {
 			}
 			return s
 		},
+		"formatBytes": func(b int64) string {
+			const (
+				kb = 1024
+				mb = 1024 * kb
+			)
+			switch {
+			case b >= mb:
+				return fmt.Sprintf("%.1f MB", float64(b)/float64(mb))
+			case b >= kb:
+				return fmt.Sprintf("%.1f KB", float64(b)/float64(kb))
+			default:
+				return fmt.Sprintf("%d B", b)
+			}
+		},
 	}
 }
 
@@ -67,6 +81,7 @@ func loadTemplates() (*templateSet, error) {
 		"templates/dashboard.html",
 		"templates/fragments/stats.html",
 		"templates/fragments/active_sessions.html",
+		"templates/fragments/recent_sessions.html",
 	)
 	if err != nil {
 		return nil, fmt.Errorf("parsing dashboard templates: %w", err)