fix: per-persona session/file isolation + onboarding route order

- session_store: store sessions under home/{user}/persona/{name}/session_data/
  instead of the shared cortex/data/sessions/ bucket
- chat endpoints: add user/persona query params to /sessions, /history/*,
  /sessions/*, /note so they resolve the correct persona context
- files router: add user/persona query params to /files and /files/{name}
  so the file browser loads the right persona's files
- app.js: pass user/persona on all session, history, and file fetches;
  move _fileParams to top-level scope so it is available everywhere
- onboarding: fix FastAPI route ordering — register /persona before /{token}
  so the literal path wins and does not get captured as a token value
- ui.py: read Emoji field from IDENTITY.md and inject into CORTEX_CONFIG
  so the header icon reflects each persona's chosen emoji
- .gitignore: exclude home/**/session_data/ (runtime state)
- migrate scott/inara sessions from cortex/data/sessions/ to session_data/

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

cortex/session_store.py

@@ -3,6 +3,7 @@ import random
 from pathlib import Path
 from datetime import datetime
 from config import settings
+from persona import persona_path
 
 
 _ADJECTIVES = [
@@ -42,7 +43,7 @@ def generate_session_id() -> str:
 
 
 def _path(session_id: str) -> Path:
-    d = settings.sessions_path()
+    d = persona_path() / "session_data"
     d.mkdir(parents=True, exist_ok=True)
     return d / f"{session_id}.json"
 
@@ -79,7 +80,7 @@ def delete(session_id: str) -> bool:
 
 
 def list_all() -> list[dict]:
-    d = settings.sessions_path()
+    d = persona_path() / "session_data"
     if not d.exists():
         return []
     results = []