Add Activity Timeline feature and database migrations

- Add Activity Timeline tab to ticket view showing chronological history
- Create getTicketTimeline() method in AuditLogModel
- Update TicketController to load timeline data
- Add timeline UI with helper functions for formatting events
- Add comprehensive timeline CSS with dark mode support
- Create migrations 007-010 for upcoming features:
  - 007: Ticket assignment functionality
  - 008: Status workflow transitions
  - 009: Ticket templates
  - 010: Bulk operations tracking

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

migrations/008_add_status_workflows.sql

@@ -0,0 +1,31 @@
+-- Migration 008: Add status workflow management
+-- Creates status_transitions table for workflow validation
+
+-- Table to define allowed status transitions
+CREATE TABLE status_transitions (
+    transition_id INT AUTO_INCREMENT PRIMARY KEY,
+    from_status VARCHAR(50) NOT NULL,
+    to_status VARCHAR(50) NOT NULL,
+    requires_comment BOOLEAN DEFAULT FALSE,
+    requires_admin BOOLEAN DEFAULT FALSE,
+    is_active BOOLEAN DEFAULT TRUE,
+    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE KEY unique_transition (from_status, to_status),
+    INDEX idx_from_status (from_status)
+);
+
+-- Insert default transitions
+INSERT INTO status_transitions (from_status, to_status, requires_comment) VALUES
+    ('Open', 'In Progress', FALSE),
+    ('Open', 'Closed', TRUE),
+    ('In Progress', 'Open', FALSE),
+    ('In Progress', 'Closed', TRUE),
+    ('Closed', 'Open', TRUE),
+    ('Closed', 'In Progress', FALSE);
+
+-- Add new status "Resolved"
+INSERT INTO status_transitions (from_status, to_status, requires_comment) VALUES
+    ('In Progress', 'Resolved', FALSE),
+    ('Resolved', 'Closed', FALSE),
+    ('Resolved', 'In Progress', TRUE),
+    ('Open', 'Resolved', FALSE);