feat(master-ui): browse experiment rollout records

[beinan]

Summary

• add paginated, exact-match rollout record filtering to the cross-shard LSM read path
• expose master APIs for experiment records and attachment-style blob downloads
• add a responsive Records workspace with filters, expandable details, pagination, and blob download controls
• avoid full-table counts by using a bounded limit + 1 scan and has_more pagination
• sync the editable lance-context entry in python/uv.lock from stale 0.4.0 to release version 0.6.3

Testing

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test -p lance-context-core filtered_listing_pages_across_shards_and_escapes_values
• cargo test -p lance-context-master routes::tests::
• npm ci && npm run build (crates/lance-context-master/ui)
• Playwright desktop and 390px mobile viewport checks
• uv --no-config lock --check
• uv run --frozen --extra dev ruff format --check . (python)
• uv run --frozen --extra dev ruff check . (python)
• uv run --frozen --extra dev pyright (python)
• cargo test --workspace
• uv run --frozen --extra tests pytest: 179 passed, 4 skipped, 1 xfailed, 10 failed in unrelated existing S3 fixtures and outdated test-double signatures