Docs: say plainly that only the bot is open source; the dashboard and API are proprietary

- README, license section and architecture no longer point to the dashboard repositories
- schema.sql is the schema for contributors; database changes only need schema.sql and a note in the PR
- self-hosting: settings without a dashboard (SQL for security thresholds, beta settings, opted-in servers)
- beta features, deployment and troubleshooting reworded for people who don't have the dashboard

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

docs/getting-started.md

@@ -57,7 +57,7 @@ TWITCH_CLIENT_ID=unused
 
 `.env` is ignored by git. Never commit it.
 
-Who the beta testers are is **not** an environment variable. It is set on the dashboard and stored in the database. See [Beta features](beta-features.md).
+Who the beta testers are is **not** an environment variable. It is stored in the database. See [Beta features](beta-features.md).
 
 ## 3. Set up the database
 
@@ -73,7 +73,7 @@ Then load the schema:
 psql "postgres://velox:velox_pwd@localhost:5432/velox?sslmode=disable" -f schema.sql
 ```
 
-`schema.sql` is written with `CREATE TABLE IF NOT EXISTS`, so running it again is safe. It is a mirror of the tables the bot uses. If you run the dashboard API as well, the API's migrations create and change these tables, and you do not need `schema.sql` at all. Read [Database](database.md) before changing a table.
+`schema.sql` is written with `CREATE TABLE IF NOT EXISTS`, so running it again is safe. It is the schema of every table the bot uses. Read [Database](database.md) before changing a table.
 
 ## 4. Run