Core Rule Set: Forgejo's ordinary requests pass by default (closes #342)

Forgejo 17.0.1's ordinary traffic, recorded in `testdata/forgejo-requests.txt` (pages signed in and out, admin pages, the API with a token, git clone and push, the generic and container registries, uploads), passes at the default settings. What Forgejo sends and gitea does not: its flash cookie `flash` joins the cookies left out, and in the new `forgejo.conf` `q` on its wiki search skips five rules. In `gitea.conf`, the API's package search joins the name searches, and `q` there also skips 932250, except on user and organisation pages. `README.md` lists Forgejo; `SPEC.md` lists the changes.

- Still refused, each tracked: `ls -la` on user and organisation pages; file and branch names in bodies while bodies are read; Forgejo's searches at a branch or tag, of releases and of job logs; other search fields not yet recorded.

Model: opus-5-5

internal/coreruleset/forgejo.conf

@@ -0,0 +1,21 @@
+# The fifteenth change: on Forgejo's paths, some fields skip the rules that
+# refused ordinary Forgejo requests there. Forgejo is a fork of gitea, and the
+# eighth change's fixes for gitea apply to its requests too, so this file holds
+# only what Forgejo sends and gitea does not. Each exclusion runs with the
+# request, before the rules it switches off, so this file is loaded before the
+# Core Rule Set's rules. Each comment names a request the rule refused.
+
+# Forgejo's search of a wiki sends the text searched for in q, which skips
+# these rules there:
+#   930120: .htaccess
+#   932120: powershell
+#   932160: /bin/sh
+#   932250: ls -la
+#   932260: python3
+SecRule REQUEST_FILENAME "@rx ^/[^/]+/[^/]+/wiki/search$" \
+    "id:900680,phase:1,pass,nolog,\
+    ctl:ruleRemoveTargetById=930120;ARGS:q,\
+    ctl:ruleRemoveTargetById=932120;ARGS:q,\
+    ctl:ruleRemoveTargetById=932160;ARGS:q,\
+    ctl:ruleRemoveTargetById=932250;ARGS:q,\
+    ctl:ruleRemoveTargetById=932260;ARGS:q"