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>

personas/inara/README.md

@@ -0,0 +1,32 @@
+# Inara — Identity & Memory Layer
+
+This directory is Inara's home. It contains everything needed to instantiate her as a
+consistent, persistent agent across any model or runtime.
+
+## Files
+
+| File | Tier | Purpose |
+|------|------|---------|
+| `SOUL.md` | Always | Core identity, traits, how she behaves |
+| `IDENTITY.md` | Always | Name, vibe, emoji — the short card |
+| `USER.md` | T1+ | Scott's profile — who she's helping |
+| `MEMORY.md` | T2+ | Curated long-term memory (keep under 4k tokens) |
+| `PROTOCOLS.md` | T2+ | Fleet rules, safety, delegation, memory management |
+| `CONTEXT_TIERS.md` | Dispatcher | Which files to load per model context size |
+| `sessions/` | T3+ | Daily session logs (raw), format: `YYYY-MM-DD.md` |
+
+## Loading Order
+
+Always load in this order to establish context before adding detail:
+1. `SOUL.md`
+2. `IDENTITY.md`
+3. `USER.md`
+4. `MEMORY.md`
+5. `PROTOCOLS.md`
+6. Session files (most recent first)
+
+See `CONTEXT_TIERS.md` for the full dispatcher spec.
+
+## Secrets
+
+Credentials, API keys, and tokens live in `.env` only — never in these files.