Sync Go client with updated Control API spec

[kennethkalmer]

Summary

Syncs this Go client library with the Control API spec changes from ably/docs#3306.

• Add 7 new rule target types: aws/lambda/before-publish, http/before-publish, hive/text-model-only, hive/dashboard, bodyguard/text-moderation, tisane/text-moderation, azure/text-moderation
• Add InvocationMode and BeforePublishConfig to support before-publish rule behavior
• Add ChatRoomFilter to rule Source
• Add APNs token-based auth fields (ApnsAuthType, ApnsSigningKey, ApnsSigningKeyId, ApnsIssuerKey, ApnsTopicHeader) to NewApp and App
• Add response-only fields to App (Created, Modified, FcmServiceAccountConfigured, ApnsCertificateConfigured, ApnsSigningKeyConfigured)
• Add MutableMessages, PopulateChannelRegistry, and AppID to Namespace
• Add ExpiresAt to Token
• Add unit tests for JSON round-tripping of all new rule types

Not addressed

• The default case in Rule.UnmarshalJSON still returns a hard error for unknown rule types. This is the existing behavior. A graceful fallback (e.g. storing as a raw/generic type) could prevent breakage when further rule types are added, but that would be a behavioral change worth discussing separately.
• Integration tests for the new rule types are not included as they require third-party API keys or special account configuration.

Test plan

• go build ./... compiles cleanly
• All existing tests pass with SKIP_INTEGRATION=true
• New TestRuleMarshalRoundTrip covers JSON marshal/unmarshal for all 7 new rule types
• TestRuleWithInvocationMode and TestSourceChatRoomFilter verify new fields deserialize correctly
• Integration tests against the live Control API (requires ABLY_ACCOUNT_TOKEN)

🤖 Generated with Claude Code

[kennethkalmer]

Closing in favour of #41 — this library is being deprecated.