Update AGENTS testing guidance

Author: cjdoris

AGENTS.md

@@ -1,9 +1,13 @@
 # Repository Instructions
 
 ## Running tests
-- **Julia tests**: Run from the project root with `julia -e 'using Pkg; Pkg.test()'`.
+- **Julia tests**: Run from the project root with `julia --project=@. -e 'using Pkg; Pkg.test()'`. Running without `--project=@.` fails because the global environment lacks the package name/UUID. Expect a warning about the General registry being unreachable in locked-down environments; the suite still finishes (PyCall tests are marked broken/Skipped).
 - **Python tests**:
-  - Copy `juliapkg-dev.json` to `juliapkg.json` before running (do **not** commit this copy).
-  - Execute with `uv run pytest -s --nbval --cov=pysrc ./pytest`. Skip `--cov` unless coverage is required.
+  - Copy `pysrc/juliacall/juliapkg-dev.json` to `pysrc/juliacall/juliapkg.json` before running (do **not** commit this copy).
+  - Execute with `uv run pytest -s --nbval ./pytest` (add `--cov=pysrc` only when coverage is needed).
+  - These tests currently require Julia 1.10–1.11. They failed here because `juliapkg` could not download metadata/install Julia through the proxy (tunnel 403) and the installed Julia 1.12.1 is outside the requested range. Without internet/proxy access to julialang.org, expect the suite to fail early while resolving Julia versions.
 
 The majority of tests live in the Julia package; Python tests cover functionality that cannot be exercised from Julia (e.g., JuliaCall-specific behavior). Run both suites—typically Julia first—in whichever order makes sense.
+
+## Meta instructions
+- When you discover environment quirks, false assumptions, or process fixes, add/update this AGENTS.md so future coding agents have the information.