Move connector privilege keys to their packages via a runtime registry

[lahirujayathilake]

Privilege keys now live where they belong. core declares its own, connectors declare theirs. A small runtime registry in pkg/models lets each package register its keys at startup, so core stays unaware of connector-specific privileges.
AMIE specific privileges have been moved to its package.

Updated the privilege names to align with :: format

Main changes

• pkg/models/privilege.go - the runtime registry: Register, IsKnownPrivilege, KnownPrivileges, core's init() self-register
• connectors/ACCESS/AMIE-Processor/server/privileges.go - first connector to declare + register its keys from its own package

Other - privilege renaming, tests updates

• Constant renames - internal/server/, internal/store/, pkg/service/
• AMIE handler wiring - connectors/ACCESS/AMIE-Processor/server/handlers.go + handlers_test.go
• Regenerated OpenAPI - api/core.openapi.yaml
• Wire format updates - dev-ops/compose/seeds/dev_users_and_roles.sql, connectors/ACCESS/AMIE-Processor/testdata/scenarios/baseline.yaml

[yasithdev]

This simplifies things a lot. LGTM! 👍🏽

[yasithdev]

@lahirujayathilake we should probably show the list of groups and the permissions they map to.

[lahirujayathilake]

@lahirujayathilake we should probably show the list of groups and the permissions they map to.

Thanks for pointing that out @yasithdev, that's really a good to have list. I'll work on that and update this PR.

[lahirujayathilake]

@yasithdev, included the privilege reference document