feat(ruleset): PHP quick-mode rules from the engine's vocabulary, measured on the development corpus

Quick mode had no PHP rules, so a PHP quick scan read the files and reported a plausible zero.
ruleset/php/rules.toml adds 13 line/statement rules built on semantic/php.toml's sinks, sources and
sanitizers (sql/wpdb, command, code_eval, unserialize, echo, file_inclusion, filesystem,
outbound_request, redirect). 9 are enabled and 4 are shadow (sql-call-composition, code-eval,
unserialize, xss-echo-input). A rule is shadow when it fired on the corpus but never at a known site.
precision_estimate is the measured lower bound.

Measured in-sample on the development corpus only (pmpro introduce/repair/benign, population-v1 PHP
cases; population-v2 was not read). Known site hit on the vulnerable pin in 4 of 5 cases (LearnPress
missed). The hit disappears on the fixed pin for pmpro and YesWiki. Numbers, per-pin files/bytes read
and the engine comparison are in benchmarks/measurements/2026-09-30-php-quick-rules/.

- fixtures php-vulnerable / php-benign plus manifests: ousast benchmark covers PHP
  (9/14 reported, 13/14 including shadow; the benign twin records 2 known false alerts)
- PHP `#` comments are comments; `#[...]` attributes are not
- the alerts task now reports PHP as quick coverage; alerts-engine keeps running the engine for PHP
  next to the quick rules (ENGINE_ALONGSIDE_QUICK)
- other languages' benchmark findings and metrics are unchanged

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo

src/openultrasast/findings.py

@@ -196,6 +196,8 @@ def _match_is_in_comment(text: str, offset: int, language: str = "") -> bool:
             return True
         comment_column = line.find("#")
         return comment_column != -1 and comment_column < column
+    if language == "php" and stripped.startswith("#") and not stripped.startswith("#["):
+        return True  # PHP also has `#` line comments; `#[...]` is a PHP 8 attribute, not a comment
     if stripped.startswith(("//", "/*", "*")):
         return True
     comment_column = line.find("//")