### Prole configuration environments

Prole treats `$PROLE_CONF` as an explicit, switchable set of isolated environment configs.

#### Directory layout

Under `$PROLE_CONF`:

```text
$PROLE_CONF/prole.cfg                 -> symlink entrypoint (active env)
$PROLE_CONF/dev/prole.cfg             -> base config (dev)
$PROLE_CONF/service/prole.cfg         -> base config (service)
$PROLE_CONF/prod/prole.cfg            -> base config (prod)
$PROLE_CONF/test/prole.cfg            -> base config (test)

# Optional overrides (conf.d-style) per environment:
$PROLE_CONF/<env>/*.cfg               -> applied as layered overrides
```

Existing code continues to read `.../prole.cfg` via the single stable entrypoint path: `$PROLE_CONF/prole.cfg`.

#### Activation (selecting the active environment)

- The active environment is determined by what `$PROLE_CONF/prole.cfg` points to.
- The Cluster Environment screen activates the selected env by updating the symlink (via `installer/prole_conf.py`).
- Switching environments only changes the symlink target; it does not overwrite any other environment’s curated files.

If the entrypoint is a regular file (legacy layout), activation preserves it as `prole.cfg.legacy.<timestamp>` and switches to the symlink-based layout.

#### Override layering (deterministic merge)

For a selected environment directory `$PROLE_CONF/<env>/`:

1. Load `$PROLE_CONF/<env>/prole.cfg` (base)
2. Load every other `*.cfg` file in the same directory, in lexicographic filename order

Later files override earlier values (last write wins). This makes overrides predictable and reviewable.

#### Why this prevents accidental namespace drift

- Tests can target an isolated environment (`test`) with its own base config and overrides.
- Environment switching is explicit (symlink target changes) and stable (entrypoint path stays the same).
- Updates that need to modify config write through the entrypoint symlink to the active environment’s base file, avoiding hidden cross-environment mutations.
- The `test` environment defaults to a non-`default` namespace (`prole-test`), reducing the chance that unit/integration runs revert to Kubernetes `default`.