Core Rule Set: random passwords pass at sign-in (closes #276)

A password manager's random password set off 35 Core Rule Set rules,
about 1 in 40 refused. The password fields the app exclusions name now
skip those rules on their paths: WordPress pwd, Drupal pass, MediaWiki
wpPassword, lgpassword and password, Mastodon's sign-in, sign-up,
password change, move and delete passwords, and Nextcloud's sign-in
password. The tests draw 2,000 random passwords from a fixed seed, plus
one rare password for each rule the 2,000 do not set off. Those that set
off a rule in a field no exclusion names are sent to every password
field. An SQL injection or a path traversal sent as a password now
passes; a script injection is still refused.

Model: opus-5-5

README.md

@@ -602,6 +602,10 @@ client's limits by tag. See "Request tags" in [`SPEC.md`](SPEC.md).
     - Nextcloud: its sync client gets through. On Nextcloud's own paths, its
       WebDAV methods, searches, file names, account names, comments and
       documents do too.
+- A password made of any printable characters gets through these forms:
+    - signing in, on WordPress, Drupal, MediaWiki and Nextcloud;
+    - signing in, signing up, changing the password, and moving or deleting the
+      account, on Mastodon.
 - `SWW_CORE_RULE_SET_EXCLUSIONS_FILE` switches single rules off for an app's own
   fields or paths.
 - Rule files are plain text, one rule to a line, edited by hand and read again