fix(context): expose history tokens and remove leaked state files

Address remaining review feedback: 1) Add HistoryTokens field to ContextUsage/ContextStats, showing history-only token count in /context and frontend UI alongside SummarizeAtTokens so users can see the actual summarization trigger comparison. 2) Remove .codebuddy/github-contribute/ state files accidentally included in the PR.

web/frontend/src/components/chat/context-usage-ring.tsx

@@ -146,6 +146,14 @@ export function ContextUsageRing({
           </div>
 
           <div className="mt-2 space-y-0.5">
+            {usage.history_tokens != null && usage.history_tokens > 0 && (
+              <div className="flex items-center justify-between text-[10px]">
+                <span className="text-muted-foreground">History</span>
+                <span className="tabular-nums">
+                  {formatTokens(usage.history_tokens)}
+                </span>
+              </div>
+            )}
             <div className="flex items-center justify-between text-[10px]">
               <span className="text-muted-foreground">{t("chat.contextCompressAt")}</span>
               <span className="tabular-nums">

web/frontend/src/features/chat/protocol.ts

@@ -78,6 +78,7 @@ function parseContextUsage(
   return {
     used_tokens: used,
     total_tokens: total,
+    history_tokens: obj.history_tokens != null ? Number(obj.history_tokens) : undefined,
     compress_at_tokens: Number(obj.compress_at_tokens) || 0,
     summarize_at_tokens: obj.summarize_at_tokens != null ? Number(obj.summarize_at_tokens) : undefined,
     used_percent: Number(obj.used_percent) || 0,

web/frontend/src/store/chat.ts

@@ -52,6 +52,7 @@ export interface ChatMessage {
 export interface ContextUsage {
   used_tokens: number
   total_tokens: number
+  history_tokens?: number
   compress_at_tokens: number
   summarize_at_tokens?: number
   used_percent: number