Creator token issuance control

Background

We do not know how much abuse there ends up being in issuing creator tokens under false channel profiles, or perhaps how much the platform wants to make such issuing a scarce activity for operational reasons.

Proposal

Allow governance to switch between a normal permissive and arestrictive token issuance policy, as follows, by adding

• new configurable storage field only_curator_approved_channels_can_issue_token: boolean in content pallet, which can be updated by content lead only.
• new field curators_granted_token_issuing: Boolean to ChannelRecord, which can only be updated by curators.
• issuing token extrinsic in content pallet checks: ensure only_curator_approved_channels_can_issue_token is true or curators_granted_token_issuing is true for the given channel.

and test + benchmarks.

Start in the content pallet and locate its configurable storage, ChannelRecord, and token-issuing extrinsic. Trace how content-lead and curator permissions are enforced, then review the pallet's tests and benchmarks. Done means the policy and channel approval state are persisted, authorization is enforced during issuance, and coverage includes tests and benchmarks.