feat: marmot protocol

[CKodidela]

Description

Adds relay support for the Marmot Protocol, the emerging standard for
E2EE group messaging on Nostr (MIPs 00–03).

The relay stays fully transport-only no MLS logic, all cryptographic complexity lives on the client side.

Kind	Role	Handling
443	Legacy KeyPackage	DefaultEventStrategy (regular storage)
10051	KeyPackage relay list	ReplaceableEventStrategy
30443	KeyPackage (addressable)	ParameterizedReplaceableEventStrategy (d-tag deduplication)
444	Welcome rumor	Blocked from direct publishing per MIP-02; delivered via existing kind:1059 gift wrap
infrastructure
445	Group Event	New GroupEventStrategy validates required h tag (nostr_group_id) before storing

#h tag subscriptions for group filtering work via the existing generic single-character tag index no migration
needed. NIP-11 relay info now advertises supported_mips: [0, 1, 2, 3].

Related Issue

Closes#579

Motivation and Context

Nostream has no support for the Marmot Protocol. Adding relay support makes nostream one of the first relays to
explicitly support it, and pairs naturally with the NIP-17+44 work from #458.

How Has This Been Tested?

• 26 new unit tests covering: GroupEventStrategy (valid event, missing h tag, multiple h tags, malformed group
  ID), factory routing for all 5 Marmot kinds, kind:444 direct-publish blocking, and
  isWelcomeRumorEvent/isMarmotGroupEvent helpers
• Full suite: 1238 tests passing (was 1212)
• pnpm run build clean
• pnpm run lint clean (285 files, no issues)

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have read the CONTRIBUTING document.
• I have added tests to cover my code changes.
• I added a changeset, or this is docs-only and I added an empty changeset.
• All new and existing tests passed.

[changeset-bot]

🦋 Changeset detected

Latest commit: ef1e7f9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
nostream	Minor

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[coveralls]

coverage: 64.503% (-0.09%) from 64.591% — CKodidela:feat/marmot-protocol into cameri:main