fix: session persistence, TTL eviction, and drift bugs

src/four-opencode-token-budget-guard.ts

@@ -77,13 +77,22 @@ export const FourTokenBudgetGuardPlugin: Plugin = async (_ctx) => {
         if (!part || part.type !== "text" || typeof part.text !== "string") return;
 
         const sessionID = props.sessionID ?? "unknown";
-        currentSessionID = sessionID;
+        // Only switch if new session is genuinely new (no tokens yet)
+        if (sessionID !== currentSessionID) {
+          const existingTokens = sessionTokens.get(sessionID);
+          if (existingTokens === 0) {
+            // New session — start fresh
+            currentSessionID = sessionID;
+          }
+          // else: keep tracking old session (compaction created new ID but tokens belong to old)
+        }
         const tokensApprox = estimateTokens(part.text);
         const cumulative = sessionTokens.add(sessionID, tokensApprox);
         const msgRole = "text-part";
 
         // Publish to plugin bus (P4d) — fire-and-forget on every token update
-        busPublisher.publish(currentSessionID, tokensApprox, sessionTokens, config).catch(() => {});
+        // Use the EVENT's sessionID, not currentSessionID (avoids drift when event has new ID)
+        busPublisher.publish(sessionID, tokensApprox, sessionTokens, config).catch(() => {});
 
         if (cumulative >= config.softLimit) {
           const isHard = cumulative >= config.hardLimit;

src/session-cache.ts

@@ -16,18 +16,14 @@ export class SessionTokenCache {
   get(sessionID: string): number {
     const entry = this.map.get(sessionID);
     if (!entry) return 0;
-    if (Date.now() - entry.lastAccess > this.ttlMs) {
-      this.map.delete(sessionID);
-      return 0;
-    }
-    entry.lastAccess = Date.now();
+    // Don't update lastAccess here — get() is read-only
     return entry.tokens;
   }
 
   add(sessionID: string, delta: number): number {
     this.evictStale();
     // Read own state BEFORE LRU eviction so we don't self-evict
-    const prev = this.get(sessionID); // touches lastAccess via get()
+    const prev = this.get(sessionID); // touches lastAccess (get is read-only)
     // If we just added a new session, may need to evict
     this.evictOldestIfFull();
     const next = prev + delta;

src/tui.tsx

@@ -54,7 +54,6 @@ function TokenMeterView() {
         <TokenMeter
           tokens={tokens()}
           softLimit={limit()}
-          colors={{ green: "#4caf50", orange: "#ff9800", red: "#f44336" }}
         />
       )}
     </box>