fix(hypatia): farm token key → secret-name (scanner FP on 'secret = …')

git-private-farm.a2ml records only the secret's NAME, but the literal
'secret = "…"' shape trips Hypatia's generic-secret detector (error-level,
fails the gate — seen on nextgen-typing#34 / oblibeny#59). Renamed the key;
no value was ever present.

https://claude.ai/code/session_01GJatEm2TVFSTBEkKXmserJ

Author: claude

.machine_readable/bot_directives/git-private-farm.a2ml

@@ -17,7 +17,7 @@ enabled = false
 workflow = ".github/workflows/instant-sync.yml"   # absent; enabled = false until it exists
 target = "hyperpolymath/.git-private-farm"
 event-type = "propagate"
-secret = "FARM_DISPATCH_TOKEN"                    # secret NAME only; value lives in repo secrets
+secret-name = "FARM_DISPATCH_TOKEN"                    # secret NAME only; value lives in repo secrets
 presence-gated = false                            # no workflow present, so no gate exists yet; gate it on addition
 
 [never-propagate]