bug: log_file_info() filename parsing produces garbled task names for deduplication

[Troubladore]

Summary

Even after fixing the header fallback (#1), the Inspect View UI may still hide files due to deduplication by task_id values parsed from filenames. The log_file_info() function populates EvalLogInfo.task and EvalLogInfo.task_id from the filename, and the client-side logs IndexedDB store uses these garbled values for grouping/deduplication — separate from the correct values in log_previews.

Context

This was observed during the investigation for #1. After renaming eval files to g2a_simlex999_{model}.eval, 13 of 17 files appeared (up from 1), but 4 remained hidden because:

• voyage_3_large → task_id="3"
• openai_3_small → task_id="3"
• openai_3_large → task_id="3"

All three collide on task_id="3", so the UI deduplicates and shows only one.

Root Cause

The logs store in IndexedDB is populated from the /api/log-files response, which uses log_file_info() filename parsing. The log_previews store is populated from actual header reads. The UI uses the logs store for list rendering and applies deduplication/filtering on task_id — which contains the garbled filename-parsed values, not the correct header values.

Relationship to #1

Issue #1 fixes the log_file_info() return values by falling back to header reads. Once #1 is implemented, log_file_info() will return correct task/task_id from the header, which means the logs store will also have correct values. This issue may be fully resolved by #1.

However, if the client-side code separately caches or derives task_id from the filename (outside of what log_file_info returns), this issue would persist.

Verification Plan

After #1 is merged:

1. Confirm that /api/log-files returns correct task/task_id for all files
2. Confirm that the logs IndexedDB store has correct values
3. Confirm no deduplication hides files
4. If all pass → close this issue as resolved by fix: Inspect View filename parsing breaks for custom .eval files #1
5. If deduplication still occurs → investigate client-side grouping logic

Acceptance Criteria

• All eval files with unique content appear as separate entries in the viewer
• No files hidden due to task_id collisions from filename parsing