Chunked log loading with Load More button

[dauglyon]

Summary

• Cap initial log fetch at 100KB using CTS seek/length query params (added in https://github.com/kbase/cdm_task_service/pull/550)
• Add "Load more" button at the bottom of the terminal output to incrementally fetch the next 100KB chunk
• Detect more content available by checking if received bytes equal the requested length
• Update mock handlers to simulate byte-level seek/length slicing

Blocked by

This PR depends on https://github.com/kbase/cdm_task_service/pull/550 being deployed, which adds seek and length query params to GET /jobs/{jobId}/log/{containerNum}/{stdout|stderr}. Until that's deployed, the params will be ignored and the full log will be returned on first fetch (with hasMore staying false since the response will be smaller than the requested length).

Test plan

• uv run jlpm build passes
• uv run jlpm lint:check passes
• uv run jlpm test passes
• Manual: enable mock mode, expand logs, verify initial content loads
• Manual: with CTS #550 deployed, verify "Load more" appears for large logs and fetches additional content

[github-actions]

Prerelease: pr-5

Wheel will be attached once the build completes. Updated on each push.