feat: multi-persona support (single Cortex, multiple users)

- Add cortex/persona.py: ContextVar-based per-request routing with
  path traversal protection and persona validation
- Migrate inara/ → personas/inara/ (git history preserved via git mv)
- config.py: add personas_root(), inara_path() delegates to personas/inara
- All 14 settings.inara_path() call sites replaced with persona_path()
- ChatRequest + OrchestrateRequest: add persona field (default: "inara")
  with validation at request entry before any processing
- memory_distiller: add optional persona param for future per-persona distill
- cron_runner/tools/cron: stamp persona on jobs, prefix APScheduler IDs
  (persona:job_id) to prevent collisions across personas
- scheduler: _load_user_crons() iterates all personas at startup

Adding a new persona: create personas/<name>/ with IDENTITY.md + SOUL.md.
Auth: handled at nginx level (inject X-Cortex-Persona header per subdomain).
Future: persona maps to Aether account_id_random for full integration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/memory_distiller.py

@@ -7,8 +7,7 @@ Inara tiered memory distillation.
 """
 import logging
 from datetime import datetime
-from pathlib import Path
-from config import settings
+from persona import persona_path as _persona_path
 
 logger = logging.getLogger(__name__)
 
@@ -24,14 +23,14 @@ def _read(path: Path) -> str:
     return path.read_text() if path.exists() else ""
 
 
-def distill_short() -> dict:
+def distill_short(persona: str | None = None) -> dict:
     """
     Roll the most recent session log files into MEMORY_SHORT.md.
     No LLM involved — pure aggregation with budget truncation.
     Files are included newest-first until the budget is reached,
     then written in chronological order (oldest first).
     """
-    inara_dir = settings.inara_path()
+    inara_dir = _persona_path(persona)
     sessions_dir = inara_dir / "sessions"
     budget = _budget_chars(settings.memory_budget_short)
 
@@ -73,13 +72,13 @@ def distill_short() -> dict:
     }
 
 
-async def distill_mid() -> dict:
+async def distill_mid(persona: str | None = None) -> dict:
     """
     Ask the LLM to summarize MEMORY_SHORT.md → MEMORY_MID.md.
     """
     from llm_client import complete
 
-    inara_dir = settings.inara_path()
+    inara_dir = _persona_path(persona)
     short_content = _read(inara_dir / "MEMORY_SHORT.md")
 
     if not short_content.strip() or "Not yet populated" in short_content:
@@ -117,13 +116,13 @@ async def distill_mid() -> dict:
     }
 
 
-async def distill_long() -> dict:
+async def distill_long(persona: str | None = None) -> dict:
     """
     Ask the LLM to integrate MEMORY_MID.md into MEMORY_LONG.md.
     """
     from llm_client import complete
 
-    inara_dir = settings.inara_path()
+    inara_dir = _persona_path(persona)
     long_content = _read(inara_dir / "MEMORY_LONG.md")
     mid_content = _read(inara_dir / "MEMORY_MID.md")