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/cli/commands.py

@@ -22,6 +22,7 @@ if sys.platform == "win32":
             pass
 
 import typer
+from loguru import logger
 from prompt_toolkit import PromptSession, print_formatted_text
 from prompt_toolkit.application import run_in_terminal
 from prompt_toolkit.formatted_text import ANSI, HTML
@@ -649,6 +650,15 @@ def gateway(
     # Set cron callback (needs agent)
     async def on_cron_job(job: CronJob) -> str | None:
         """Execute a cron job through the agent."""
+        # Dream is an internal job — run directly, not through the agent loop.
+        if job.name == "dream":
+            try:
+                await agent.dream.run()
+                logger.info("Dream cron job completed")
+            except Exception:
+                logger.exception("Dream cron job failed")
+            return None
+
         from nanobot.agent.tools.cron import CronTool
         from nanobot.agent.tools.message import MessageTool
         from nanobot.utils.evaluator import evaluate_response
@@ -768,6 +778,21 @@ def gateway(
 
     console.print(f"[green]✓[/green] Heartbeat: every {hb_cfg.interval_s}s")
 
+    # Register Dream cron job (always-on, idempotent on restart)
+    dream_cfg = config.agents.defaults.dream
+    if dream_cfg.model:
+        agent.dream.model = dream_cfg.model
+    agent.dream.max_batch_size = dream_cfg.max_batch_size
+    agent.dream.max_iterations = dream_cfg.max_iterations
+    from nanobot.cron.types import CronJob, CronPayload, CronSchedule
+    cron.register_system_job(CronJob(
+        id="dream",
+        name="dream",
+        schedule=CronSchedule(kind="cron", expr=dream_cfg.cron, tz=config.agents.defaults.timezone),
+        payload=CronPayload(kind="system_event"),
+    ))
+    console.print(f"[green]✓[/green] Dream: cron {dream_cfg.cron}")
+
     async def run():
         try:
             await cron.start()