chore: delete applied migrations (001-002, 004-005 all applied to DB)

All SQL migration files have been applied and recorded in the migrations
tracking table. Folder intentionally empty — migrate.php kept as runner
for future one-time schema changes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

migrations/001_add_indexes.sql

@@ -1,48 +0,0 @@
--- Migration: Add Performance Indexes
--- Run this migration to improve query performance on common operations
-
--- Single-column indexes for filtering
--- These support the most common WHERE clauses in getAllTickets()
-
--- Status filtering (very common - used in almost every query)
-CREATE INDEX IF NOT EXISTS idx_tickets_status ON tickets(status);
-
--- Category and type filtering
-CREATE INDEX IF NOT EXISTS idx_tickets_category ON tickets(category);
-CREATE INDEX IF NOT EXISTS idx_tickets_type ON tickets(type);
-
--- Priority filtering
-CREATE INDEX IF NOT EXISTS idx_tickets_priority ON tickets(priority);
-
--- Date-based filtering and sorting
-CREATE INDEX IF NOT EXISTS idx_tickets_created_at ON tickets(created_at);
-CREATE INDEX IF NOT EXISTS idx_tickets_updated_at ON tickets(updated_at);
-
--- User filtering
-CREATE INDEX IF NOT EXISTS idx_tickets_created_by ON tickets(created_by);
-CREATE INDEX IF NOT EXISTS idx_tickets_assigned_to ON tickets(assigned_to);
-
--- Visibility filtering (used in every authenticated query)
-CREATE INDEX IF NOT EXISTS idx_tickets_visibility ON tickets(visibility);
-
--- Composite indexes for common query patterns
--- These are more efficient than single indexes for combined filters
-
--- Status + created_at (common sorting with status filter)
-CREATE INDEX IF NOT EXISTS idx_tickets_status_created ON tickets(status, created_at);
-
--- Assigned_to + status (for "my open tickets" queries)
-CREATE INDEX IF NOT EXISTS idx_tickets_assigned_status ON tickets(assigned_to, status);
-
--- Visibility + status (visibility filtering with status)
-CREATE INDEX IF NOT EXISTS idx_tickets_visibility_status ON tickets(visibility, status);
-
--- ticket_comments table
--- Optimize comment retrieval by ticket
-CREATE INDEX IF NOT EXISTS idx_comments_ticket_created ON ticket_comments(ticket_id, created_at);
-
--- Audit log indexes (if audit_log table exists)
--- Optimize audit log queries
-CREATE INDEX IF NOT EXISTS idx_audit_entity ON audit_log(entity_type, entity_id);
-CREATE INDEX IF NOT EXISTS idx_audit_user ON audit_log(user_id, created_at);
-CREATE INDEX IF NOT EXISTS idx_audit_action ON audit_log(action, created_at);

migrations/002_add_comment_threading.sql

@@ -1,19 +0,0 @@
--- Migration: Add comment threading support
--- Adds parent_comment_id for reply/thread functionality
-
--- Add parent_comment_id column for threaded comments
-ALTER TABLE ticket_comments
-ADD COLUMN parent_comment_id INT NULL DEFAULT NULL AFTER comment_id;
-
--- Add foreign key constraint (self-referencing for thread hierarchy)
-ALTER TABLE ticket_comments
-ADD CONSTRAINT fk_parent_comment
-FOREIGN KEY (parent_comment_id) REFERENCES ticket_comments(comment_id)
-ON DELETE CASCADE;
-
--- Add index for efficient thread retrieval
-CREATE INDEX idx_parent_comment ON ticket_comments(parent_comment_id);
-
--- Add thread_depth column to track nesting level (prevents infinite recursion issues)
-ALTER TABLE ticket_comments
-ADD COLUMN thread_depth TINYINT UNSIGNED NOT NULL DEFAULT 0 AFTER parent_comment_id;

migrations/004_add_ticket_watchers.sql

@@ -1,10 +0,0 @@
--- Migration: Add ticket watchers table
--- Allows users to subscribe to ticket updates and receive Matrix notifications.
-
-CREATE TABLE IF NOT EXISTS ticket_watchers (
-    ticket_id  INT          NOT NULL,
-    user_id    INT          NOT NULL,
-    created_at TIMESTAMP    NOT NULL DEFAULT CURRENT_TIMESTAMP,
-    PRIMARY KEY (ticket_id, user_id),
-    INDEX idx_watcher_user (user_id)
-);

migrations/005_add_fulltext_search.sql

@@ -1,6 +0,0 @@
--- Migration: Add FULLTEXT index on ticket title and description
--- Replaces LIKE '%term%' with MATCH ... AGAINST for dramatically better search
--- performance and relevance ranking at scale.
--- MyISAM not needed — InnoDB supports FULLTEXT since MySQL 5.6.
-
-ALTER TABLE tickets ADD FULLTEXT INDEX ft_title_description (title, description);