Core Rule Set: Ghost's ordinary requests pass by default (closes #357)

Ghost 6.76.0's ordinary traffic, recorded in `testdata/ghost-requests.txt`,
passes at the default settings and while bodies are read. It covers public
pages, members' sign-up and sign-in, the admin, the editor saving and
publishing posts and pages with code blocks and HTML cards, tags, settings,
staff invitations, uploads, newsletter settings, and both APIs. Ghost's
fixes, in the new `ghost.conf`, let through `filter`, the member `search`
and the embed `url` in the query, and plain text, addresses, articles, code
injection and passwords in JSON bodies. A `<script>` element and a
`javascript:` link stay refused in articles and code injection. `SWW_APPS`
names Ghost `ghost`. `README.md` lists Ghost; `SPEC.md` lists its fixes.

Model: opus-5-5

internal/coreruleset/coreruleset.go

@@ -185,6 +185,9 @@ var nextcloudDirectives string
 //go:embed forgejo.conf
 var forgejoDirectives string
 
+//go:embed ghost.conf
+var ghostDirectives string
+
 // apps are the apps whose fixes sww has, by the name SWW_APPS gives each.
 // flash is Forgejo's name for gitea_flash.
 //
@@ -196,6 +199,7 @@ var apps = map[string]app{
 		cookies:    []string{"flash"},
 		forkOf:     "gitea",
 	},
+	"ghost": {directives: ghostDirectives},
 	"gitea": {
 		directives: giteaDirectives,
 		cookies:    []string{"gitea_flash", "redirect_to"},