This commit addresses all critical and important issues from the PR review:

## Critical Issues Fixed

1. **Removed fallback to deterministic handle construction**
- Production now ONLY resolves handles from PLC (source of truth)
- If PLC resolution fails, indexing fails with error (no fallback)
- Prevents creating communities with incorrect handles in federated scenarios
- Test mode (nil resolver) still uses deterministic construction for testing

2. **Deleted unnecessary migration 016**
- Migration only updated column comment (no schema change)
- Documentation now lives in code comments instead
- Keeps migration history focused on actual schema changes

## Important Issues Fixed

3. **Extracted duplicated handle construction to helper function**
- Created `constructHandleFromProfile()` helper
- Validates hostedBy format (must be did:web)
- Returns empty string if invalid, triggering repository validation
- DRY principle now followed

4. **Added repository validation for empty handles**
- Repository now fails fast if consumer tries to insert empty handle
- Makes contract explicit: "handle is required (should be constructed by consumer)"
- Prevents silent failures

5. **Fixed E2E test to remove did/handle from record data**
- Removed 'did' and 'handle' fields from test record
- Added missing 'owner' field
- Test now accurately reflects real-world PDS records (atProto compliant)

6. **Added comprehensive PLC resolution integration tests**
- Created mock identity resolver for testing
- Test: Successfully resolves handle from PLC
- Test: Fails when PLC resolution fails (verifies no fallback)
- Test: Validates invalid hostedBy format in test mode
- All tests verify the production code path

## Test Strategy Improvements

7. **Updated all consumer tests to use mock resolver**
- Tests now exercise production PLC resolution code path
- Mock resolver pre-configured with DID → handle mappings
- Only one test uses nil resolver (validates edge case)
- E2E test uses real identity resolver with local PLC

8. **Added setupIdentityResolver() helper for test infrastructure**
- Reusable helper for configuring PLC resolution in tests
- Uses local PLC at http://localhost:3002 for E2E tests
- Production-like testing without external dependencies

## Architecture Summary

**Production flow:**
Record (no handle) → PLC lookup → Handle from PLC → Cache in DB
↓ (if fails)
Error + backfill later

**Test flow with mock:**
Record (no handle) → Mock PLC lookup → Pre-configured handle → Cache in DB

**Test mode (nil resolver):**
Record (no handle) → Deterministic construction → Validate format → Cache in DB

All tests pass. Server builds successfully.

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

Following atProto best practices, community profile records now only contain
user-controlled data. Handles are mutable and resolved from DIDs via PLC, so
they should not be stored in immutable records. Member/subscriber counts are
AppView-computed stats, not record data.

Changes:
- Remove 'handle' field from community profile record creation
- Remove 'handle' field from community profile record updates
- Remove 'memberCount' and 'subscriberCount' from profile records
- Update E2E test to not expect handle in PDS record
- Update consumer test mock data to match new record schema

AppView caching (Go structs) still maintains these fields for performance:
- service.go:190 - Community struct keeps Handle field
- community_consumer.go:159,241 - Consumer reads handle for caching

This matches Bluesky's app.bsky.actor.profile pattern where handles are
resolved from DIDs, not stored in profile records.

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

- Update cross-reference tests to use new defs locations
- Remove handle field from actor profile test data
- Update invalid test case to check for missing createdAt instead of handle
- Clean up test data for removed lexicons (block, saved, preferences)

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

Actor changes:
- Remove handle from actor.profile record (resolved from DID, not stored)
- Remove geoLocation from actor.profile (not implemented)
- Remove verification fields from profile (AppView concern, not record data)
- Remove federation fields from profile (AppView concern, not record data)
- Remove moderation fields from profile (AppView concern, not record data)
- Update actor.getProfile to return profileViewDetailed from defs
- Update actor.updateProfile to remove geoLocation reference

Community changes:
- Remove handle from community.profile record (resolved from DID, not stored)
- Remove memberCount, subscriberCount from record (AppView cached stats)
- Remove federatedFrom, federatedId from record (AppView metadata)
- Remove federation and contentRules from record (not implemented)
- Update community.get to return communityViewDetailed from defs
- Update community.list to return communityView array from defs

Key principle: Records contain only user-controlled data. Computed stats,
cached values, and viewer state live in AppView views (defs.json), not records.

Following atProto best practices per:
https://github.com/bluesky-social/atproto/discussions/4245

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

- Add social.coves.actor.defs.json with profileView, profileViewDetailed,
profileStats, viewerState, and geoLocation definitions
- Add social.coves.community.defs.json with communityView, communityViewDetailed,
communityStats, and viewerState definitions
- Remove unimplemented actor lexicons: block, blockUser, unblockUser, saved,
saveItem, unsaveItem, getSaved, preferences
- Remove duplicate actor.subscription (replaced by community.subscription)

Following atProto best practices: reusable definitions in defs.json,
removing unimplemented features from pre-production codebase.

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

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

Applied atProto best practices from https://github.com/bluesky-social/atproto/discussions/4245

Changes:
- getMembers.json: Changed 'enum' to 'knownValues' for sort parameter to allow schema evolution
- profile.json: Removed 'visibility' and 'moderationType' from required fields (both have defaults)

These changes improve forward compatibility and follow atProto lexicon design guidelines
while maintaining full backward compatibility with existing code.

Impact: Zero breaking changes - all tests pass, service layer already handles defaults.

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