Track phase retries in test runs

When a test phase fails and is retried, you can now store every attempt with a retry_count field and filter retries out of your analytics.

• Added retry_count to phases: set it to track which attempt each phase represents (0 = first, 1 = first retry). Defaults to 0 when omitted.
• Added "Exclude retries" toggle on all insights charts (Cpk, cycle time, failures, control charts, duration) to focus on final attempts only
• Retried phases show expandable attempt tabs in the phase detail view
• OpenHTF retries are detected automatically from repeated phase names, no changes needed in test scripts