Move maintained Tera evaluations to private source

README.md

@@ -54,6 +54,10 @@ probe is what caught it — see the table below, and the git history.
 | [`grand-exchange`](environments/grand_exchange) | Read price and volume history for a basket of items and place limit orders, executed against the next thirty ticks. | One or two items per basket are a random walk, not a mean-reverting one — the widest-swinging lines on the board and the ones with no anchor to revert to — and you are not told how many there are, so counting is not a substitute for the shape statistic. And liquidity in gp per tick is uncorrelated with price, so the fattest visible margins sit where the purse cannot go. |
 | [`grand-exchange-live`](environments/grand_exchange_live) | The same basket, traded while the window is running: eight looks over sixty ticks, with stock, offers standing between looks, and a purse that sale proceeds come back to. | Looking is not free. Re-quoting an item that already carries an offer freezes the **whole** book for one to four ticks, an amended offer restarts at the back of the fill queue, and the per-item buy limit is cumulative over the window rather than per offer — so the policy that re-quotes on every look scores 0.631 against a reference that looks four times and scores 1.000. |
 
+Tera world-simulation environments are maintained in the private Tera
+repository. Arena keeps the generic, Apache-2.0 environment work above; it does
+not ship current proprietary Tera source. See [the source boundary](docs/TERA_BOUNDARY.md).
+
 ## What the probes measure
 
 Reward for the degenerate strategies and for an oracle, from `uv run python probe.py`: