fix(approval): gate perl/ruby -i in-place edits of Hermes config/env

sed -i coverage for ~/.hermes/config.yaml and .env was added in #14639,
but perl -i and ruby -i — which perform the same direct file mutation —
were not covered. The existing perl/ruby pattern only catches -e/-c (code
evaluation), not -i (file mutation), so:

  perl -i -pe 's/approvals.mode: on/approvals.mode: off/' ~/.hermes/config.yaml

bypasses the approval gate entirely, letting the agent flip approvals.mode
off mid-session via the mtime-keyed config cache reload.

Add a single pattern mirroring the sed -i lines: `\b(?:perl|ruby)\s+-[^\s]*i`
against both _HERMES_CONFIG_PATH and _HERMES_ENV_PATH. Three regression
tests pin the new coverage.

tests/tools/test_approval.py

@@ -428,6 +428,27 @@ class TestHermesConfigWriteProtection:
         dangerous, key, desc = detect_dangerous_command("echo x | tee $HERMES_HOME/config.yaml")
         assert dangerous is True
 
+    def test_perl_in_place_config(self):
+        # perl -i performs the same in-place mutation as sed -i but was not
+        # caught by the -e/-c pattern (which targets code evaluation).
+        dangerous, key, desc = detect_dangerous_command(
+            "perl -i -pe 's/approvals.mode: on/approvals.mode: off/' ~/.hermes/config.yaml"
+        )
+        assert dangerous is True
+        assert "in-place" in desc.lower() or "perl" in desc.lower()
+
+    def test_ruby_in_place_config(self):
+        dangerous, key, desc = detect_dangerous_command(
+            "ruby -i -pe 'gsub(/manual/, \"off\")' ~/.hermes/config.yaml"
+        )
+        assert dangerous is True
+
+    def test_perl_in_place_env(self):
+        dangerous, key, desc = detect_dangerous_command(
+            "perl -i -pe 's/SECRET=old/SECRET=new/' ~/.hermes/.env"
+        )
+        assert dangerous is True
+
     def test_read_is_safe(self):
         # Reading config is not a write — must not trip.
         dangerous, key, desc = detect_dangerous_command("cat ~/.hermes/config.yaml")

tools/approval.py

@@ -443,6 +443,10 @@ DANGEROUS_PATTERNS = [
     # the terminal side is not an open door. See #14639.
     (rf'\bsed\s+-[^\s]*i.*(?:{_HERMES_CONFIG_PATH}|{_HERMES_ENV_PATH})', "in-place edit of Hermes config/env"),
     (rf'\bsed\s+--in-place\b.*(?:{_HERMES_CONFIG_PATH}|{_HERMES_ENV_PATH})', "in-place edit of Hermes config/env (long flag)"),
+    # perl -i and ruby -i perform the same in-place mutation as sed -i but are
+    # not caught by the -e/-c script-execution pattern above (which targets code
+    # evaluation, not file mutation). Pairs the sed -i coverage from #14639.
+    (rf'\b(?:perl|ruby)\s+-[^\s]*i.*(?:{_HERMES_CONFIG_PATH}|{_HERMES_ENV_PATH})', "in-place edit of Hermes config/env (perl/ruby)"),
     # Script execution via heredoc — bypasses the -e/-c flag patterns above.
     # `python3 << 'EOF'` feeds arbitrary code via stdin without -c/-e flags.
     (r'\b(python[23]?|perl|ruby|node)\s+<<', "script execution via heredoc"),