chore: remove unused commits.json and set verified as default

commits.json was a doc mirror never referenced by any workflow/action
(main.yml, root-variants.yml, and scripts use PIN_* in main.yml directly).
main.yml commit_mode default was latest, now verified for audited reproducible builds; latest/update remain as manual options.

.github/config/commits.json

@@ -1,14 +0,0 @@
-{
-  "kernelsu": {
-    "dev": "5a4a71874caaad06aa126f761c93391de1d32361"
-  },
-  "susfs": {
-    "gki-android12-5.10": "86114db0c49f20fa7857b8b559f3ab87cbc2d00d",
-    "gki-android13-5.10": "9101b676971fcb4dc1c4746cebd90d816de13524",
-    "gki-android13-5.15": "e4bd49f708108cc829fe7ca079312ea8fefa89f8",
-    "gki-android14-5.15": "4a427619566885eb70517ba76b3a7d742db18fc9",
-    "gki-android14-6.1": "9bf72ec2c83d40f194b936cabbc64ce342e005bf",
-    "gki-android15-6.6": "2df41de789026a6422521606402576507c687435",
-    "gki-android16-6.12": "75a613850178234c6c7595d1db8211716a011a2e"
-  }
-}

.github/workflows/main.yml

@@ -45,7 +45,7 @@ on:
           - latest
           - verified
           - update
-        default: latest
+        default: verified
       root_flavor:
         description: "Root Flavor"
         type: choice