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.

pkg/agent/agent_command.go

@@ -352,6 +352,7 @@ func (al *AgentLoop) buildCommandsRuntime(
 			return &commands.ContextStats{
 				UsedTokens:        usage.UsedTokens,
 				TotalTokens:       usage.TotalTokens,
+				HistoryTokens:     usage.HistoryTokens,
 				CompressAtTokens:  usage.CompressAtTokens,
 				SummarizeAtTokens: usage.SummarizeAtTokens,
 				UsedPercent:       usage.UsedPercent,

pkg/agent/context_usage.go

@@ -64,12 +64,9 @@ func computeContextUsage(agent *AgentInstance, sessionKey string) *bus.ContextUs
 	// summarizeAt = soft summarization trigger: matches maybeSummarize's
 	// threshold (contextWindow * SummarizeTokenPercent / 100).
 	//
-	// NOTE: The engine's maybeSummarize compares this threshold against
-	// history-message tokens only (via estimateTokens), while UsedTokens
-	// (shown in /context) includes system prompt, summary, and tool
-	// definitions on top of history tokens.  A "Used > SummarizeAt" display
-	// does not necessarily mean summarization will fire — the engine may
-	// still consider the history-token budget to be under threshold.
+	// The engine compares this against history-message tokens ONLY (not
+	// UsedTokens).  HistoryTokens is exposed alongside UsedTokens so the
+	// UI can show both values and avoid user confusion.
 	summarizeAt := contextWindow * agent.SummarizeTokenPercent / 100
 	if summarizeAt <= 0 {
 		summarizeAt = compressAt
@@ -86,6 +83,7 @@ func computeContextUsage(agent *AgentInstance, sessionKey string) *bus.ContextUs
 	return &bus.ContextUsage{
 		UsedTokens:        usedTokens,
 		TotalTokens:       contextWindow,
+		HistoryTokens:     historyTokens,
 		CompressAtTokens:  compressAt,
 		SummarizeAtTokens: summarizeAt,
 		UsedPercent:       usedPercent,