refactor: one code path behind doctor legacy-state migrations (#120716)

* refactor(doctor): prefer manifest route-state owners

* refactor(doctor): unify config repair declarations

* refactor(doctor): unify legacy state migrations

* fix(doctor): satisfy migration pipeline guards

* fix(plugin-sdk): keep doctor adapter inside boundary

extensions/slack/openclaw.plugin.json

@@ -1,8 +1,7 @@
 {
   "id": "slack",
   "doctorContract": {
-    "legacyConfigRules": true,
-    "normalizeCompatibilityConfig": true
+    "configRepair": true
   },
   "name": "Slack",
   "description": "OpenClaw Slack channel plugin for channels, DMs, commands, and app events.",