feat(agent): two-stage memory system with Dream consolidation

Replace single-stage MemoryConsolidator with a two-stage architecture:

- Consolidator: lightweight token-budget triggered summarization,
  appends to HISTORY.md with cursor-based tracking
- Dream: cron-scheduled two-phase processor that analyzes HISTORY.md
  and updates SOUL.md, USER.md, MEMORY.md via AgentRunner with
  edit_file tools for surgical, fault-tolerant updates

New files: MemoryStore (pure file I/O), Dream class, DreamConfig,
/dream and /dream-log commands. 89 tests covering all components.

nanobot/command/builtin.py

@@ -47,7 +47,7 @@ async def cmd_status(ctx: CommandContext) -> OutboundMessage:
     session = ctx.session or loop.sessions.get_or_create(ctx.key)
     ctx_est = 0
     try:
-        ctx_est, _ = loop.memory_consolidator.estimate_session_prompt_tokens(session)
+        ctx_est, _ = loop.consolidator.estimate_session_prompt_tokens(session)
     except Exception:
         pass
     if ctx_est <= 0:
@@ -75,13 +75,47 @@ async def cmd_new(ctx: CommandContext) -> OutboundMessage:
     loop.sessions.save(session)
     loop.sessions.invalidate(session.key)
     if snapshot:
-        loop._schedule_background(loop.memory_consolidator.archive_messages(snapshot))
+        loop._schedule_background(loop.consolidator.archive(snapshot))
     return OutboundMessage(
         channel=ctx.msg.channel, chat_id=ctx.msg.chat_id,
         content="New session started.",
     )
 
 
+async def cmd_dream(ctx: CommandContext) -> OutboundMessage:
+    """Manually trigger a Dream consolidation run."""
+    loop = ctx.loop
+    try:
+        did_work = await loop.dream.run()
+        content = "Dream completed." if did_work else "Dream: nothing to process."
+    except Exception as e:
+        content = f"Dream failed: {e}"
+    return OutboundMessage(
+        channel=ctx.msg.channel, chat_id=ctx.msg.chat_id, content=content,
+    )
+
+
+async def cmd_dream_log(ctx: CommandContext) -> OutboundMessage:
+    """Show the Dream consolidation log."""
+    loop = ctx.loop
+    store = loop.consolidator.store
+    log = store.read_dream_log()
+    if not log:
+        # Check if Dream has ever processed anything
+        if store.get_last_dream_cursor() == 0:
+            content = "Dream has not run yet."
+        else:
+            content = "No dream log yet."
+    else:
+        content = f"## Dream Log\n\n{log}"
+    return OutboundMessage(
+        channel=ctx.msg.channel,
+        chat_id=ctx.msg.chat_id,
+        content=content,
+        metadata={"render_as": "text"},
+    )
+
+
 async def cmd_help(ctx: CommandContext) -> OutboundMessage:
     """Return available slash commands."""
     return OutboundMessage(
@@ -100,6 +134,8 @@ def build_help_text() -> str:
         "/stop — Stop the current task",
         "/restart — Restart the bot",
         "/status — Show bot status",
+        "/dream — Manually trigger Dream consolidation",
+        "/dream-log — Show Dream consolidation log",
         "/help — Show available commands",
     ]
     return "\n".join(lines)
@@ -112,4 +148,6 @@ def register_builtin_commands(router: CommandRouter) -> None:
     router.priority("/status", cmd_status)
     router.exact("/new", cmd_new)
     router.exact("/status", cmd_status)
+    router.exact("/dream", cmd_dream)
+    router.exact("/dream-log", cmd_dream_log)
     router.exact("/help", cmd_help)