chore(env): rename test env sample

docs/adrs/adr-0007-test-framework.md

@@ -50,7 +50,7 @@ Two independent timeout layers, ordered so the finer one fires first.
 
 **Layer 1 — `libtest` per-case timeout (primary).** [`apis/libtest.lua`](../../packages/trapos-test/apis/libtest.lua) races each test case against a timer with `parallel.waitForAny(runner, timer)`. The default is `DEFAULT_TIMEOUT_SECONDS = 3`. When the timer wins, the case fails with a distinct message containing the token `libtest timeout` and, in `--verbose`, an extra `TIMEOUT … (libtest)` diagnostic. `--timeout <seconds>` overrides the default; `--no-timeout` disables the layer. `runtest` forwards both flags to each case script. This only interrupts cases that yield (the usual hang); a non-yielding CPU loop cannot be preempted in ComputerCraft.
 
-**Layer 2 — shell watchdog (backstop).** The `Justfile` `test:` recipe keeps its `TRAPOS_TEST_TIMEOUT_SECONDS` watchdog as an independent double-check. Its default matches the libtest default (`.env.test` ships `3`; the recipe falls back to `3`) so libtest fires first for yielding cases in normal runs and the watchdog only catches what Lua cannot — a non-yielding loop, a wedged libtest, or a deliberately bypassed case. Its SIGTERM message is worded differently from the `libtest timeout` message, so the two layers are never confused.
+**Layer 2 — shell watchdog (backstop).** The `Justfile` `test:` recipe keeps its `TRAPOS_TEST_TIMEOUT_SECONDS` watchdog as an independent double-check. Its default matches the libtest default (`env.sample` ships `3`; the recipe falls back to `3`) so libtest fires first for yielding cases in normal runs and the watchdog only catches what Lua cannot — a non-yielding loop, a wedged libtest, or a deliberately bypassed case. Its SIGTERM message is worded differently from the `libtest timeout` message, so the two layers are never confused.
 
 ### How to write tests properly
 

just/install.just

@@ -39,5 +39,5 @@ generate-env:
                 printf '%s\n' "$line"
                 ;;
         esac
-    done < .env.test > .env
+    done < env.sample > .env
     printf '%s\n' 'Generated .env'

just/test.just

@@ -20,7 +20,7 @@ _craftos-test *args: stage
     #!/usr/bin/env bash
     set -uo pipefail
 
-    if [ -f .env.test ]; then set -a; . ./.env.test; set +a; fi
+    if [ -f env.sample ]; then set -a; . ./env.sample; set +a; fi
 
     pretty=0
     has_output=0
@@ -98,7 +98,7 @@ _timeout-fixture script shell_timeout extra_flag expect: check-install stage
     #!/usr/bin/env bash
     set -uo pipefail
     repo='{{justfile_directory()}}'
-    if [ -f "$repo/.env.test" ]; then set -a; . "$repo/.env.test"; set +a; fi
+    if [ -f "$repo/env.sample" ]; then set -a; . "$repo/env.sample"; set +a; fi
     rom_arg=""
     if [ "$(uname -s)" = "Darwin" ]; then
         rom_arg="--rom /Applications/CraftOS-PC.app/Contents/Resources"