[oleksandr-nc]

The guides say HaRP matches routes by url only and ignores verb, and that the PHP proxy refuses a request with 404. Since nextcloud/HaRP#149 HaRP takes the first route whose url and verb both match, accepts HEAD where GET is listed and answers a method no route of the path lists with 405. nextcloud/app_api#1144 made the PHP proxy accept HEAD on GET routes too, and nextcloud/app_api#1149 raises the HaRP version AppAPI requires to 0.4.8.

Changes

• exapp-contract.md: how HaRP 0.4.8+ and the PHP proxy pick a route by url and verb, when a refused request gets 404 and when 405, that HaRP's url regex is case-sensitive, and to list every method a route serves in its verb.
• harp-operations.md and SKILL.md: 405 in the status tables and in troubleshooting, and the 0.4.8 minimum from fix(harp): require HaRP 0.4.8 in the version check app_api#1149 with its one-hour cache.