Add --analysis-root filter to parse failures script

Filter parse failures to only those for announcements that are in
production but missing from the archive. This eliminates noise from
rejections of events from other relays that don't affect migration.

Before: 223 parse failures (all rejections from all relays)
After: 18 parse failures (only for missing announcements)

The filter works by:
1. Reading missing announcements from comparison data
2. Extracting event IDs from production announcements JSON
3. Filtering parse failures to only matching event IDs

0 files changed, 0 insertions, 0 deletions