fix: drop --tests flag from make verify (verify.py rewrite removed it)

verify.py no longer takes the --tests directory argument — test
discovery now comes from each comp-req's verified-by: list of bazel
targets, so there is no "tests directory" to walk. The Makefile still
passed the obsolete flag, causing CI to fail with "unrecognized
arguments: --tests verification" before the gate could even run.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: avrabe

Makefile

@@ -49,7 +49,7 @@ wit:
 # reports PASSED / FAILED / MISSING per artifact. Exits 1 if any
 # FAILED or MISSING.
 verify:
-	@$(PYTHON) tools/verify.py --artifacts artifacts --tests verification
+	@$(PYTHON) tools/verify.py --artifacts artifacts
 
 # ── sigil-signed release manifest (optional) ────────────────────────
 attest: