refactor(contracts): gate the coverage compile-skip on solidity-coverage's run flag

Trigger the test-phase noCompile on solidity-coverage's own __SOLIDITY_COVERAGE_RUNNING HRE flag
instead of our COVERAGE env var. The flag is true only during an actual coverage run, so a stray
COVERAGE=true in the environment can no longer make a plain hardhat test skip compilation and run
stale artifacts; and if the internal flag ever changes the worst case is the redundant compile
returning, a perf regression rather than a correctness bug.

Signed-off-by: Miguel_LZPF <miguel.carpena@io.builders>

Author: MiguelLZPF

packages/ats/contracts/tasks/compile.ts

@@ -30,12 +30,20 @@ task(TASK_COMPILE, "🛠  Compile and regenerate the contract registry.", async
  * solidity-coverage compiles the instrumented sources itself (its own `env.run(TASK_COMPILE)`),
  * then runs `env.run(TASK_TEST)` — and Hardhat's TASK_TEST compiles AGAIN as a dependency. That
  * second pass is a full ~60s instrumented solc rebuild per coverage shard for no benefit: the
- * instrumented artifacts already exist from solidity-coverage's own compile. The coverage task
- * wrapper (hardhat.config.ts) sets `COVERAGE=true`, so when that is set we force `noCompile`,
- * leaving the instrumented build untouched and the measured coverage identical.
+ * instrumented artifacts already exist from solidity-coverage's own compile. Force `noCompile` for
+ * the test phase of a coverage run, leaving the instrumented build untouched and the measured
+ * coverage identical.
+ *
+ * Gate on solidity-coverage's own `__SOLIDITY_COVERAGE_RUNNING` flag (set on the HRE for the
+ * duration of `hardhat coverage`) rather than our `COVERAGE` env var: the flag is authoritative —
+ * true only during a real coverage run, so a stray `COVERAGE=true` in the environment can't make a
+ * plain `hardhat test` skip compilation and run stale artifacts — and if the internal flag ever
+ * disappears the worst case is the redundant compile returning (a perf regression, not a
+ * correctness bug).
  */
-task(TASK_TEST).setAction(async (args, _hre, runSuper) => {
-  if (process.env.COVERAGE === "true") {
+task(TASK_TEST).setAction(async (args, hre, runSuper) => {
+  const coverageRunning = (hre as { __SOLIDITY_COVERAGE_RUNNING?: boolean }).__SOLIDITY_COVERAGE_RUNNING === true;
+  if (coverageRunning) {
     return runSuper({ ...args, noCompile: true });
   }
   return runSuper(args);