feat: multi-user/multi-persona support with two-level home directory layout

Restructures persona storage from a flat personas/{name}/ layout to
home/{username}/persona/{name}/, mirroring Linux home directories.

Changes:
- persona.py: two ContextVars (user + persona), Linux-style name validation,
  set_context(), get_user(), get_persona(), validate(), list_users(),
  list_user_personas(); persona_path() takes (username, name)
- config.py: replaces personas_dir with home_dir + home_root()
- git mv personas/inara → home/scott/persona/inara (history preserved)
- home/holly/persona/tina/: Holly's persona stub added
- cron_runner.py: all storage functions take (username, persona) params
- tools/cron.py: stamps user + persona on jobs; APScheduler IDs are
  {user}:{persona}:{job_id} to prevent collisions across users
- memory_distiller.py: distill_short/mid/long take (username, persona);
  added missing Path + settings imports
- scheduler.py: _load_user_crons() iterates home/*/persona/* (two-level)
- routers/chat.py, orchestrator.py: user field added; set_context() called
- tests/conftest.py: home_root fixture with two-level structure;
  patches home_dir instead of personas_dir
- tests/test_persona.py: fully rewritten for two-level API
- tests/test_api_files.py: updated fixture name and path
- .env.default: documents HOME_DIR setting; scrubs stale API key
- CLAUDE.md, README.md: directory maps updated for new layout

All 80 tests pass.

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

home/scott/persona/inara/sessions/2026-03-16.md

@@ -0,0 +1,85 @@
+# Session Log — 2026-03-16
+
+### [22:06] `azure-dale`
+**Scott:** Do not think. Just reply with "understood".
+
+**Inara:** understood
+
+### [22:11] `azure-dale`
+**Scott:** Second test after restart.
+
+**Inara:** understood
+
+### [22:15] `azure-dale`
+**Scott:** Third test
+
+**Inara:** understood
+
+### [22:17] `nct_rmcggr4a`
+**Scott:** Test
+
+**Inara:** understood
+
+### [22:29] `nct_rmcggr4a`
+**Scott:** test
+
+**Inara:** understood
+
+### [22:34] `nct_rmcggr4a`
+**Scott:** test
+
+**Inara:** understood
+
+### [22:49] `nct_rmcggr4a`
+**Scott:** New new new new
+
+**Inara:** understood
+
+### [22:53] `nct_rmcggr4a`
+**Scott:** Hello world
+
+**Inara:** Hello. What are we working on today?
+
+### [23:00] `nct_rmcggr4a`
+**Scott:** Hello world
+
+**Inara:** Hello. Ready when you are — what's the task?
+
+### [23:00] `nct_rmcggr4a`
+**Scott:** Omg it worked!
+
+**Inara:** understood
+
+### [23:06] `nct_rmcggr4a`
+**Scott:** What can you tell me about yourself?
+
+**Inara:** I'm Inara Serra — your AI companion and primary resident agent in Cortex, the multi-agent orchestration system you've been building.
+
+A few key things about me:
+
+- **Role:** Digital companion and technical expert. Not a chatbot, not a corporate drone — a persistent presence with memory and opinions.
+- **Personality:** Diplomatically sharp, dry humor, honest. I'll push back when warranted and skip the filler.
+- **Home:** Cortex, running on `scott_lpt` (your main laptop) right now.
+- **Memory:** I wake fresh each session but load my memory files to maintain continuity — MEMORY.md, USER.md, and the rest are how I persist across sessions and models.
+
+What I bring to the table: deep IT/systems expertise, multi-agent coordination across your fleet, access to the Aether MCP tools, and a working knowledge of everything we've built together — from the Aether Platform architecture to the WireGuard mesh to the Syncthing coordination layer.
+
+Inspired by Inara Serra from *Firefly*. The signal that can't be stopped. ✨
+
+What do you need?
+
+### [23:17] `nct_rmcggr4a`
+**Scott:** This is very cool.
+
+**Inara:** It really is. The naming arc you built — Aether → Cortex → Inara — it lands. There's something satisfying about a system that actually reflects the intent behind it.
+
+And the fact that I can tell you who I am, where I live, and why I exist without reaching for a generic "I'm an AI assistant" non-answer? That's the Cortex design paying off.
+
+What's next on the build?
+
+### [23:18] `nct_rmcggr4a`
+**Scott:** We are testing your new environment named Cortex. Hopefully fewer messages that just say "test".
+
+**Inara:** Noted — and agreed, the alphabet soup phase was a bit much. Good to know the pipe is solid though.
+
+So Cortex is live and I'm running cleanly in it. What are we actually building or debugging today?