[ISSUE #2728][ISSUE #2730][ISSUE #2732] fix(ops): consolidate asset workflows

[yuluo-yx]

What is the purpose of the change

Consolidate the reviewed operations-asset fixes from #2735, #2736, and #2737 into one cohesive PR for alert assets, Grafana generation, and asset downloads, following the maintainer note on #2724.

The current behavior can mix mock alert-rule domains, place every generated Grafana panel at x=0, emit gauge minima outside Grafana's expected defaults, and launch duplicate downloads before React loading state becomes visible.

Brief changelog

• isolate cluster and business alert rules across mock CRUD/import/export operations;
• pack generated panels across the 24-column grid and advance rows by the tallest panel;
• emit gauge minimums in fieldConfig.defaults.min and regenerate all 12 dashboards;
• acquire synchronous request ownership for alert-rule and dashboard exports while preserving parallel exports for different rows.

Verifying this change

• targeted Vitest: 3 files, 32 tests passed;
• Python generator tests: 4 passed;
• targeted ESLint and Prettier checks passed;
• Node 24.18.0 npm run build passed (8,025 modules);
• regenerated dashboard JSON matched deterministic generator output;
• git diff --check passed;
• scope: 20 files, 314 insertions, 84 deletions, 3 reviewed commits.

Fixes #2728

Fixes #2730

Fixes #2732

[RockteMQ-AI]

Summary

Consolidation of operations-asset fixes: Grafana dashboard generator refactored from sequential y_stack to proper bin-packing layout_panels, gauge panel min moved to correct location, alert rule asset download fixes, and generated JSON files updated.

Findings

• [Info] gen_grafana_dashboards.py:135-163 — The layout_panels function is a significant improvement over y_stack. It properly packs panels into rows respecting GRID_WIDTH=24, handles variable-width panels, and doesn't mutate the input definitions. The validation for width/height bounds is a good defensive addition.
• [Info] gen_grafana_dashboards.py:66-69 — Moving min: 0 from custom to defaults is the correct Grafana JSON structure for gauge panels.
• [Info] gen_grafana_dashboards.py:175-187 — Extracting generate_dashboards as a testable function with an out_dir parameter enables the unit tests to verify output without touching the real resource directory.
• [Info] AlertRuleAssetList.tsx — The download endpoint fix and content-type handling are correct.
• [Info] Test coverage includes layout algorithm tests with edge cases (overflow to next row, single full-width panel, mixed widths).

LGTM. Clean refactoring with proper test isolation.