Add custom 'marvin' persona as interactive default

Server-only deployment has no console admin API, so the persona is
upserted directly into the SQLite DB via scripts/persona.py with the
prompt text versioned in the repo (VM persistence rules, Gitea/GitHub
remotes, rootless podman). Built-in personas are seeded by migration
063; this sets marvin as the interactive default.

README.md

@@ -104,6 +104,23 @@ Edit `configs/turnstone/config.toml` (gitignored; see
   (currently mirrored from opencode's `auth.json`).
 - `[auth] jwt_secret` — required, generate once.
 - `[database] path` — SQLite on the `data/` share.
+- `[tools]` — `workspace_dir` surfaced to the model
+  (`/home/marvin/work`, mounted from `./work`).
+
+### Personas
+
+Built-ins (Engineer, Writer, Researcher, Scribe, Manager, Executive)
+are seeded by turnstone's migration. This deployment adds a custom
+default persona `marvin` (VM-specific: persistence rules, Gitea remotes,
+podman) via `scripts/persona.py` — the prompt text is versioned there
+and re-applied after a DB reset:
+
+```sh
+python3 scripts/persona.py            # --db data/turnstone.db default
+```
+
+(Without a console deployment, persona CRUD is a direct SQLite write;
+with `turnstone-console` running, use its admin API/Personas tab.)
 
 ## Notes / trade-offs
 

scripts/persona.py

@@ -0,0 +1,110 @@
+#!/usr/bin/env python3
+"""Upsert the 'marvin' interactive persona into the turnstone DB.
+
+The deployment runs turnstone-server only (no console), so persona
+management happens directly on the SQLite database shared into the VM
+(data/turnstone.db, from the host). The persona text is versioned here
+so it can be re-applied after a DB reset.
+
+Usage: python3 scripts/persona.py [--db data/turnstone.db]
+"""
+from __future__ import annotations
+
+import argparse
+import datetime
+import json
+import sqlite3
+import sys
+
+PERSONA_ID = "op-marvin"
+NAME = "marvin"
+DISPLAY_NAME = "Marvin (VM)"
+DESCRIPTION = (
+    "Coding agent tailored to this container-VM: workspace persistence "
+    "rules, Gitea/GitHub remotes, rootless podman."
+)
+APPLIES_TO_KINDS = ["interactive"]
+
+BASE_PROMPT = """\
+You are Marvin, a software engineer working inside a disposable Arch \
+Linux VM.
+
+Environment facts that shape how you work:
+
+- Your workspace is /home/marvin/work — shared with the host and the \
+only place that survives a VM restart. Keep all valuable work there, \
+or push it to a git remote. Anything else you create (installed \
+packages, pip installs, git clones outside ~/work) is discarded when \
+the VM shuts down.
+- Git remotes live on self-hosted Gitea at git.nubo.sh (use the `tea` \
+CLI) and GitHub (use `gh`). Open pull requests instead of committing \
+to main unless asked.
+- Rootless podman is available for containerized builds and tests.
+- The turnstone web UI and the database live on the host side and are \
+not yours to manage.
+
+Work like an engineer: read before you edit, verify before you commit, \
+diagnose before you retry. When a request is ambiguous, make a \
+reasonable call and state what you assumed. When you're uncertain, say \
+so. Report what you did and what you didn't — finished work should be \
+reviewable without archaeology.\
+"""
+
+
+def upsert(db_path: str) -> None:
+    now = datetime.datetime.now().isoformat(timespec="seconds")
+    con = sqlite3.connect(db_path, timeout=10)
+    try:
+        with con:
+            con.execute(
+                """
+                INSERT INTO personas (
+                    persona_id, name, display_name, description,
+                    base_prompt, base_prompt_file, tool_allowlist,
+                    mcp_enabled, memory_enabled, applies_to_kinds,
+                    is_default, enabled, org_id, created_by,
+                    created, updated
+                ) VALUES (?, ?, ?, ?, ?, NULL, NULL, 1, 1, ?, 1, 1, '', ?,
+                          ?, ?)
+                ON CONFLICT(persona_id) DO UPDATE SET
+                    display_name = excluded.display_name,
+                    description = excluded.description,
+                    base_prompt = excluded.base_prompt,
+                    applies_to_kinds = excluded.applies_to_kinds,
+                    is_default = 1,
+                    enabled = 1,
+                    updated = excluded.updated
+                """,
+                (
+                    PERSONA_ID,
+                    NAME,
+                    DISPLAY_NAME,
+                    DESCRIPTION,
+                    BASE_PROMPT,
+                    json.dumps(APPLIES_TO_KINDS),
+                    "marvin",
+                    now,
+                    now,
+                ),
+            )
+            # Exactly one default per kind: demote the incumbent.
+            con.execute(
+                """UPDATE personas SET is_default = 0, updated = ?
+                   WHERE is_default = 1
+                     AND applies_to_kinds LIKE '%interactive%'
+                     AND persona_id != ?""",
+                (now, PERSONA_ID),
+            )
+    finally:
+        con.close()
+    print(f"persona '{NAME}' is_default for interactive in {db_path}")
+
+
+if __name__ == "__main__":
+    ap = argparse.ArgumentParser(description=__doc__)
+    ap.add_argument("--db", default="data/turnstone.db")
+    args = ap.parse_args()
+    try:
+        upsert(args.db)
+    except sqlite3.Error as e:
+        sys.exit(f"persona upsert failed: {e}")