Gitea setup: Core Rule Set blocks attacks, not ordinary Gitea traffic (closes #198)

The Gitea setup runs the Core Rule Set in block mode. Rules that refused
ordinary Gitea requests are switched off only where they misfired:

- deploy/gitea/crs-exclusions.conf, loaded through the new setting
  SWWAF_CORE_RULE_SET_EXCLUSIONS_FILE before the Core Rule Set's rules,
  covers Gitea's search, file-name and branch-name fields, Referer, file
  paths, API attachment names and Actions artifact uploads;
- smallwebwaf's defaults gain a seventh change: the registry upload
  path's from parameter skips 932260.

A file that cannot be read, does not parse or names an id from 900000
to 900999 stops servewaf at start, in every mode. internal/waf's tests
and script/gitea-setup send the recorded requests in
internal/waf/testdata/gitea-requests.txt and three attacks.

Model: opus-5-5

deploy/gitea/compose.yaml

@@ -104,11 +104,12 @@ services:
             # address of an automation fleet on another host here too; without
             # that, it is counted like any client.
             SWWAF_ALLOW_NETS: 10.99.0.128/25,fd10:99:0:0:8000::/65
-            # In block mode the Core Rule Set refuses everyday Gitea searches
-            # and file names, and 31 refusals in a minute ban the address.
-            SWWAF_WAF_MODE: detect
+            # The Core Rule Set's exclusions for Gitea's searches, file names
+            # and branch names.
+            SWWAF_CORE_RULE_SET_EXCLUSIONS_FILE: /etc/smallwebwaf/crs-exclusions.conf
         volumes:
             - servewaf-state:/var/lib/smallwebwaf
+            - ./crs-exclusions.conf:/etc/smallwebwaf/crs-exclusions.conf:ro
         networks:
             - shared
         logging: *logging