refactor: move config_path from root into install_methods

Migrated all 80 app JSON files to place config_path inside each
install_methods object instead of at the root level. This allows
different install methods (e.g. Debian vs Alpine) to have distinct
config paths.

Also updated AGENTS.md JSON structure example to reflect the change.

json/protonmail-bridge.json

@@ -12,12 +12,12 @@
   "documentation": "https://proton.me/support/bridge-cli-guide",
   "website": "https://proton.me/mail/bridge",
   "logo": "https://cdn.jsdelivr.net/gh/selfhst/icons@main/webp/proton-mail.webp",
-  "config_path": "",
   "description": "Proton Mail Bridge runs a local IMAP/SMTP service that lets traditional mail clients access a Proton mailbox. This LXC runs Bridge headless and forwards IMAP/SMTP to the LAN using systemd socket activation (systemd-socket-proxyd).",
   "install_methods": [
     {
       "type": "default",
       "script": "ct/protonmail-bridge.sh",
+      "config_path": "",
       "resources": {
         "cpu": 2,
         "ram": 1024,