feat(wcl): add encounter selection for uploads

[RobDeFlop]

Summary

• Add a scan-and-select modal for raid encounters, Mythic+ dungeons, and PvP activities before upload.
• Filter one-shot uploads to the selected fight sequences and expose progress/error events.
• Preserve existing-data backfill for live logging and handle log rotation safely.
• Add structural sequence parsing and regression coverage for Mythic+ markers, including failed runs.
• Display activity timestamps, durations, status, difficulty, keystone level, and PvP format in the selection UI.

Why

Warcraft Logs combat logs can contain many non-encounter events, and Mythic+ markers are not reliably represented by the simplified event parser. Scan and upload now share the same raw-log sequence boundaries, so M+ runs are classified and selectable instead of appearing as other fights.

Validation

• cargo fmt --check
• cargo test --lib (35 tests)
• cargo clippy --all-targets -- -D warnings
• bunx tsc --noEmit
• bun run build
• git diff --check