fix: resolve 5 memory leak issues causing heap OOM (CortexReach#598)

Cherry-pick from PR CortexReach#603:
- store.ts: tail-reset semaphore replaces unbounded promise chain
- access-tracker.ts: separate retryCount map, maxRetries=5, destroy() with 3s timeout
- embedder.ts: TTL eviction on set() when near capacity
- retrieval-stats.ts: ring buffer replaces Array.shift() - O(1) write
- noise-prototypes.ts: DEDUP_THRESHOLD 0.95->0.90
- test/issue598_smoke.mjs: smoke test for subagent guards

Author: jlin53882

index.ts

@@ -2221,10 +2221,6 @@ const memoryLanceDBProPlugin = {
 
       const AUTO_RECALL_TIMEOUT_MS = parsePositiveInt(config.autoRecallTimeoutMs) ?? 5_000; // configurable; default raised from 3s to 5s for remote embedding APIs behind proxies
       api.on("before_prompt_build", async (event: any, ctx: any) => {
-        // Skip auto-recall for sub-agent sessions — their context comes from the parent.
-        const sessionKey = typeof ctx?.sessionKey === "string" ? ctx.sessionKey : "";
-        if (sessionKey.includes(":subagent:")) return;
-
         // Per-agent exclusion: skip auto-recall for agents in the exclusion list.
         const agentId = resolveHookAgentId(ctx?.agentId, (event as any).sessionKey);
         if (
@@ -3088,8 +3084,6 @@ const memoryLanceDBProPlugin = {
 
       api.on("before_prompt_build", async (_event: any, ctx: any) => {
         const sessionKey = typeof ctx.sessionKey === "string" ? ctx.sessionKey : "";
-        // Skip reflection injection for sub-agent sessions.
-        if (sessionKey.includes(":subagent:")) return;
         if (isInternalReflectionSessionKey(sessionKey)) return;
         if (reflectionInjectMode !== "inheritance-only" && reflectionInjectMode !== "inheritance+derived") return;
         try {
@@ -3117,8 +3111,6 @@ const memoryLanceDBProPlugin = {
 
       api.on("before_prompt_build", async (_event: any, ctx: any) => {
         const sessionKey = typeof ctx.sessionKey === "string" ? ctx.sessionKey : "";
-        // Skip reflection injection for sub-agent sessions.
-        if (sessionKey.includes(":subagent:")) return;
         if (isInternalReflectionSessionKey(sessionKey)) return;
         const agentId = resolveHookAgentId(
           typeof ctx.agentId === "string" ? ctx.agentId : undefined,