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/routers/files.py

@@ -2,9 +2,9 @@
 Read/write the Inara identity markdown files.
 Only whitelisted filenames are accessible — no path traversal possible.
 """
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter, HTTPException, Query
 from pydantic import BaseModel
-from persona import persona_path
+from persona import persona_path, set_context, validate as validate_persona
 
 router = APIRouter()
 
@@ -22,6 +22,15 @@ ALLOWED = {
 }
 
 
+def _resolve(user: str, persona: str) -> None:
+    """Validate and set context from query params. Raises HTTPException on bad input."""
+    try:
+        u, p = validate_persona(user, persona)
+        set_context(u, p)
+    except ValueError as e:
+        raise HTTPException(status_code=404, detail=str(e))
+
+
 def _path(filename: str):
     if filename not in ALLOWED:
         raise HTTPException(status_code=404, detail=f"File not found: {filename}")
@@ -29,11 +38,15 @@ def _path(filename: str):
 
 
 @router.get("/files")
-async def list_files() -> dict:
-    inara_dir = persona_path()
+async def list_files(
+    user: str = Query("scott"),
+    persona: str = Query("inara"),
+) -> dict:
+    _resolve(user, persona)
+    persona_dir = persona_path()
     files = []
     for name in sorted(ALLOWED):
-        p = inara_dir / name
+        p = persona_dir / name
         files.append({
             "name": name,
             "exists": p.exists(),
@@ -43,7 +56,12 @@ async def list_files() -> dict:
 
 
 @router.get("/files/{filename}")
-async def get_file(filename: str) -> dict:
+async def get_file(
+    filename: str,
+    user: str = Query("scott"),
+    persona: str = Query("inara"),
+) -> dict:
+    _resolve(user, persona)
     p = _path(filename)
     if not p.exists():
         raise HTTPException(status_code=404, detail=f"{filename} does not exist")
@@ -55,7 +73,13 @@ class FileWrite(BaseModel):
 
 
 @router.put("/files/{filename}")
-async def save_file(filename: str, req: FileWrite) -> dict:
+async def save_file(
+    filename: str,
+    req: FileWrite,
+    user: str = Query("scott"),
+    persona: str = Query("inara"),
+) -> dict:
+    _resolve(user, persona)
     p = _path(filename)
     p.write_text(req.content)
     return {"ok": True, "name": filename, "size": len(req.content)}