Add buildDeletedCommentView method that creates placeholder views
for deleted comments with blanked content but preserved threading.

Update buildThreadViews to include deleted comments instead of
skipping them, enabling child comments to remain visible with
their parent showing "[deleted]".

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

Add SoftDeleteWithReason and SoftDeleteWithReasonTx methods that:
- Blank content, facets, embed, and labels on deletion
- Set deletion_reason and deleted_by metadata
- Validate deletion reason is author or moderator
- Support optional transaction for atomic operations
- Return rows affected for idempotency checks

Update all thread queries to include deleted comments by removing
deleted_at IS NULL filter, preserving thread structure.

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

Add SoftDeleteWithReason to Repository interface for content-blanking
soft deletes that preserve thread structure.

Add RepositoryTx interface with SoftDeleteWithReasonTx method for
transactional operations, enabling atomic delete + count updates
in the Jetstream consumer.

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

Add IsDeleted, DeletionReason, and DeletedAt fields to CommentView
for rendering deleted comment placeholders in thread views.
Frontend can display "[deleted]" or "[removed by moderator]" based
on the deletion_reason field.

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

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

Add DeletionReasonAuthor and DeletionReasonModerator constants.
Add DeletionReason and DeletedBy fields to Comment struct for
tracking who deleted a comment and why.

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

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

Add migration 021 that:
- Creates deletion_reason enum type (author, moderator)
- Adds deletion_reason and deleted_by columns to comments table
- Backfills existing deleted comments as author-deleted
- Removes deleted_at IS NULL filter from thread indexes to preserve structure
- Adds indexes for deletion_reason and deleted_by for moderation queries

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

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

Add complete comment write operations (create/update/delete) with:
- XRPC lexicons for all three operations
- Service layer with validation and authorization
- HTTP handlers with proper error mapping
- Comprehensive unit and integration tests
- Proper grapheme counting with uniseg library

Follows write-forward architecture: Client → Handler → Service → PDS → Jetstream → DB

Add two P3 technical debt items for future optimistic locking:

1. Implement PutRecord in PDS Client
- Add swapRecord/swapCommit for optimistic locking
- Handle conflict responses gracefully

2. Migrate UpdateComment to Use PutRecord
- Blocked by PutRecord implementation
- Will prevent concurrent update races

These items are not urgent since concurrent comment updates are rare,
but will improve robustness when implemented.

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

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

Add github.com/rivo/uniseg for proper Unicode grapheme cluster counting.
This replaces utf8.RuneCountInString() with uniseg.GraphemeClusterCount()
to correctly handle complex Unicode characters like emojis with modifiers.

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

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

Add integration tests for comment write operations testing:
- CreateComment XRPC endpoint validation
- UpdateComment authorization and validation
- DeleteComment authorization and success

Fix existing integration tests to use NewCommentServiceWithPDSFactory
with nil factory for read-only test scenarios. This allows tests that
only exercise the read path (GetComments) to work without OAuth setup.

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

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

Add comprehensive unit tests for CreateComment, UpdateComment, and
DeleteComment service methods including:

- Validation tests (empty content, content too long, invalid URIs)
- Authorization tests (ownership verification for update/delete)
- Collection validation to prevent cross-collection attacks
- Success path tests with mock PDS client

Also updates existing comment service tests for constructor changes.

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

- Add RegisterCommentRoutes for comment write XRPC endpoints
- Wire comment service with OAuth dependencies in main.go
- All write endpoints require OAuth authentication middleware

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

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