Comprehensive lexicon extensibility fixes to ensure alpha-readiness
and future-proof schema evolution without requiring V2 migrations.

Key Changes:
- Fixed all closed enums → knownValues (moderationType, visibility, sort)
- Made moderator roles and permissions extensible
- Added authentication documentation to all endpoints
- Removed invalid membership record references
- Documented technical decisions in PRD_GOVERNANCE.md

This locks down the lexicon schemas for alpha while enabling future
beta features (sortition moderation, new visibility modes, moderator
tiers) without breaking changes.

Per atProto style guide (bluesky-social/atproto#4245): enum sets
cannot be extended without breaking schema evolution rules.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Membership tracking is AppView-only data, not atProto records.

Changes:
- Removed membershipUri field from community.get viewerState
- Updated member field description to clarify it's AppView-computed
- Removed membership lexicon file (already deleted)
- Removed membership test data files (already deleted)

Rationale:
- Membership/reputation is indexed from user activity, not explicit records
- No need for AT-URI reference to non-existent record type
- Clarifies that membership status is computed by AppView, not stored in repo

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Per atProto style guide: endpoint descriptions should mention if
authentication is required and whether responses are personalized.

Changes:
- create.json: Added "Requires authentication."
- update.json: Added "Requires authentication and moderator/admin permissions."
- subscribe.json: Added "Requires authentication."
- unsubscribe.json: Added "Requires authentication."
- get.json: Added "Authentication optional; viewer state will be included if authenticated."
- list.json: Added "Authentication optional; viewer state will be included if authenticated."

This improves developer experience by making auth requirements
explicit without requiring documentation lookup.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

BREAKING: This is a pre-alpha schema fix. Must be applied before any
moderator records are created.

Changes to social.coves.community.moderator:
- Change role from enum to knownValues (enables future role types)
- Change permissions from enum to knownValues (enables new permissions)
- Add maxLength: 64 to both fields per atProto style guide

Future extensibility examples:
- Roles: "owner", "trainee", "emeritus"
- Permissions: "manage_bots", "manage_flairs", "manage_automoderator"

Documented in PRD_GOVERNANCE.md:
- Technical decision rationale
- atProto style guide reference
- Future beta phase extensibility plan
- Security considerations

This enables Beta Phase 2 (Moderator Tiers & Permissions) without
requiring V2 schema migration or breaking existing records.

Per atProto style guide (bluesky-social/atproto#4245): enum sets
cannot be extended without breaking schema evolution rules.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

- Change sort from closed enum to knownValues
- Add maxLength: 64 per atProto style guide

This enables future sort algorithms without breaking changes:
- "trending" - Recent activity spike detection
- "recommended" - Personalized AI recommendations
- "nearby" - Geo-based sorting

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

- Change visibility from closed enum to knownValues
- Apply to community.profile (record), create, and update endpoints
- Add maxLength: 64 per atProto style guide

This enables future visibility modes without breaking changes:
- "followers-only" - Only subscribers can see
- "instance-only" - Only same-instance users
- "invite-only" - Requires invite code

Files changed:
- community/profile.json (record schema)
- community/create.json (procedure)
- community/update.json (procedure)

Per atProto style guide: closed enums block schema evolution.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>