chore: rename project Roundtable → Steward

Renames the Python package directory, CLI command, env var prefix,
docker-compose service/container/image, Postgres role/db, and all
visible branding. Marketing form is "Fabled Steward".

Clean break from the previous rebrand: drops the fabledscryer→roundtable
import shim in __init__.py and the FABLEDSCRYER_* env var fallback in
config.py and migrations/env.py. Env vars are now STEWARD_* only.

Heads-up for existing deployments:
- Postgres user/db renamed fabledscryer → steward in docker-compose.yml.
  Existing volumes need the role/db renamed inside Postgres, or override
  POSTGRES_USER/POSTGRES_DB to keep the old names.
- Host-agent systemd unit is now steward-agent.service. Existing agents
  keep running under the old name; reinstall to switch.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/plugins/writing-a-plugin.md

@@ -46,7 +46,7 @@ config:
 
 ## Step 3: Define Models (if needed)
 
-If your plugin stores data, define SQLAlchemy models using the shared `Base` from `roundtable.models.base`.
+If your plugin stores data, define SQLAlchemy models using the shared `Base` from `steward.models.base`.
 
 ```python
 # plugins/myplugin/models.py
@@ -55,7 +55,7 @@ import uuid
 from datetime import datetime
 from sqlalchemy import String, Float, DateTime
 from sqlalchemy.orm import Mapped, mapped_column
-from roundtable.models.base import Base
+from steward.models.base import Base
 
 
 class MyPluginMetric(Base):
@@ -79,7 +79,7 @@ Generate the initial migration:
 # From the project root
 alembic --config alembic.ini revision \
     --autogenerate \
-    --head=roundtable@head \
+    --head=steward@head \
     --branch-label=myplugin \
     -m "myplugin initial"
 ```
@@ -106,8 +106,8 @@ Keep task logic in a separate file so `__init__.py` stays clean.
 # plugins/myplugin/scheduler.py
 from __future__ import annotations
 import logging
-from roundtable.core.scheduler import ScheduledTask
-from roundtable.core.alerts import record_metric
+from steward.core.scheduler import ScheduledTask
+from steward.core.alerts import record_metric
 
 logger = logging.getLogger(__name__)
 
@@ -174,8 +174,8 @@ async def _fetch_value(url: str) -> float:
 ```python
 # plugins/myplugin/routes.py
 from quart import Blueprint, current_app, render_template
-from roundtable.auth.middleware import require_role
-from roundtable.models.users import UserRole
+from steward.auth.middleware import require_role
+from steward.models.users import UserRole
 from .models import MyPluginMetric
 
 myplugin_bp = Blueprint("myplugin", __name__, template_folder="templates")
@@ -215,7 +215,7 @@ Templates live in `plugins/myplugin/templates/myplugin/` (the extra nesting avoi
 ```html
 {# plugins/myplugin/templates/myplugin/index.html #}
 {% extends "base.html" %}
-{% block title %}My Plugin — Roundtable{% endblock %}
+{% block title %}My Plugin — Steward{% endblock %}
 {% block content %}
 <div class="page-title">My Plugin</div>
 {% for row in rows %}
@@ -283,7 +283,7 @@ On next startup, the plugin will be loaded, its migrations applied, and its blue
 `record_metric()` is how plugins feed data into the alert pipeline. Any metric you write here can be the target of an alert rule created in the UI.
 
 ```python
-from roundtable.core.alerts import record_metric
+from steward.core.alerts import record_metric
 
 # Must be inside an active transaction
 async with session.begin():
@@ -302,11 +302,11 @@ async with session.begin():
 
 ## Auth in Routes
 
-Use the `@require_role` decorator from `roundtable.auth.middleware`:
+Use the `@require_role` decorator from `steward.auth.middleware`:
 
 ```python
-from roundtable.auth.middleware import require_role
-from roundtable.models.users import UserRole
+from steward.auth.middleware import require_role
+from steward.models.users import UserRole
 
 @myplugin_bp.get("/admin-only")
 @require_role(UserRole.admin)
@@ -325,13 +325,13 @@ Role hierarchy: `admin > operator > viewer`. Requiring `viewer` grants access to
 
 ## Publishing to the Catalog
 
-The official plugin catalog is hosted at `https://git.fabledsword.com/bvandeusen/Roundtable-plugins`. Anyone can submit a plugin by opening a pull request — first-party and third-party plugins are treated identically by the catalog system.
+The official plugin catalog is hosted at `https://git.fabledsword.com/bvandeusen/Steward-plugins`. Anyone can submit a plugin by opening a pull request — first-party and third-party plugins are treated identically by the catalog system.
 
 ### Repo layout
 
 ```
-roundtable-plugins/
-├── index.yaml          ← catalog index — the only file Roundtable fetches
+steward-plugins/
+├── index.yaml          ← catalog index — the only file Steward fetches
 ├── myplugin/
 │   ├── plugin.yaml
 │   ├── __init__.py
@@ -381,7 +381,7 @@ myplugin.zip
 Generate the zip and its checksum:
 
 ```bash
-cd roundtable-plugins
+cd steward-plugins
 zip -r myplugin.zip myplugin/
 sha256sum myplugin.zip   # paste this into index.yaml checksum_sha256
 ```