fix(hooks): remove debug console.log statements from session-memory hook

Remove development debug console.log statements from the session-memory
hook handler. These debug statements were polluting the console output
during normal operation.

Changes:
- Remove 13 debug console.log statements that were logging internal state
- Add proper SubsystemLogger for trace-level logging of completion message
- Keep console.error for actual failure cases (consistent with other hooks)
- Remove unused currentSessionId variable that was only used for logging

The hook now uses the project's standard logging infrastructure
(createSubsystemLogger) for any operational logging, which can be enabled
via log level configuration when debugging is needed.

Tested: All 9 session-memory hook tests pass

src/hooks/bundled/session-memory/handler.ts

@@ -14,6 +14,9 @@ import { resolveAgentWorkspaceDir } from "../../../agents/agent-scope.js";
 import { resolveAgentIdFromSessionKey } from "../../../routing/session-key.js";
 import { resolveHookConfig } from "../../config.js";
 import type { HookHandler } from "../../hooks.js";
+import { createSubsystemLogger } from "../../../logging/subsystem.js";
+
+const log = createSubsystemLogger("hooks:session-memory");
 
 /**
  * Read recent messages from session file for slug generation
@@ -68,8 +71,6 @@ const saveSessionToMemory: HookHandler = async (event) => {
   }
 
   try {
-    console.log("[session-memory] Hook triggered for /new command");
-
     const context = event.context || {};
     const cfg = context.cfg as MoltbotConfig | undefined;
     const agentId = resolveAgentIdFromSessionKey(event.sessionKey);
@@ -88,13 +89,8 @@ const saveSessionToMemory: HookHandler = async (event) => {
       string,
       unknown
     >;
-    const currentSessionId = sessionEntry.sessionId as string;
     const currentSessionFile = sessionEntry.sessionFile as string;
 
-    console.log("[session-memory] Current sessionId:", currentSessionId);
-    console.log("[session-memory] Current sessionFile:", currentSessionFile);
-    console.log("[session-memory] cfg present:", !!cfg);
-
     const sessionFile = currentSessionFile || undefined;
 
     // Read message count from hook config (default: 15)
@@ -110,10 +106,8 @@ const saveSessionToMemory: HookHandler = async (event) => {
     if (sessionFile) {
       // Get recent conversation content
       sessionContent = await getRecentSessionContent(sessionFile, messageCount);
-      console.log("[session-memory] sessionContent length:", sessionContent?.length || 0);
 
       if (sessionContent && cfg) {
-        console.log("[session-memory] Calling generateSlugViaLLM...");
         // Dynamically import the LLM slug generator (avoids module caching issues)
         // When compiled, handler is at dist/hooks/bundled/session-memory/handler.js
         // Going up ../.. puts us at dist/hooks/, so just add llm-slug-generator.js
@@ -123,7 +117,6 @@ const saveSessionToMemory: HookHandler = async (event) => {
 
         // Use LLM to generate a descriptive slug
         slug = await generateSlugViaLLM({ sessionContent, cfg });
-        console.log("[session-memory] Generated slug:", slug);
       }
     }
 
@@ -131,14 +124,11 @@ const saveSessionToMemory: HookHandler = async (event) => {
     if (!slug) {
       const timeSlug = now.toISOString().split("T")[1]!.split(".")[0]!.replace(/:/g, "");
       slug = timeSlug.slice(0, 4); // HHMM
-      console.log("[session-memory] Using fallback timestamp slug:", slug);
     }
 
     // Create filename with date and slug
     const filename = `${dateStr}-${slug}.md`;
     const memoryFilePath = path.join(memoryDir, filename);
-    console.log("[session-memory] Generated filename:", filename);
-    console.log("[session-memory] Full path:", memoryFilePath);
 
     // Format time as HH:MM:SS UTC
     const timeStr = now.toISOString().split("T")[1]!.split(".")[0];
@@ -166,11 +156,10 @@ const saveSessionToMemory: HookHandler = async (event) => {
 
     // Write to new memory file
     await fs.writeFile(memoryFilePath, entry, "utf-8");
-    console.log("[session-memory] Memory file written successfully");
 
-    // Log completion (but don't send user-visible confirmation - it's internal housekeeping)
+    // Log completion using subsystem logger (visible when log level is trace/debug)
     const relPath = memoryFilePath.replace(os.homedir(), "~");
-    console.log(`[session-memory] Session context saved to ${relPath}`);
+    log.trace(`Session context saved to ${relPath}`);
   } catch (err) {
     console.error(
       "[session-memory] Failed to save session memory:",