feat(migrations): add plugin-owned Hermes import

* feat: add migration providers

* feat: offer Hermes migration during onboarding

* feat(hermes): map imported config surfaces

* feat(onboard): require fresh migration imports

* docs(cli): clarify Hermes import coverage

* chore(migrations): rename Hermes importer package

* chore(migrations): rewire Hermes importer id

* fix(migrations): redact migration JSON details

* fix(hermes): use provider runtime for config imports

* test(hermes): cover missing source planning

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

docs/docs.json

@@ -1545,6 +1545,7 @@
                       "cli/gateway",
                       "cli/health",
                       "cli/logs",
+                      "cli/migrate",
                       "cli/onboard",
                       "cli/reset",
                       "cli/secrets",