wf1f AIS local sea level shows zero — EAIS and WAIS sub-files not summed

[Ttheegela]

Describe the bug
AIS local sea level for workflow wf1f displayed as zero or was missing entirely. The IPCCAR5/ar5AIS module does not produce a combined AIS_localsl.nc file — only EAIS_localsl.nc and WAIS_localsl.nc exist as separate files.

Root cause
The dashboard attempted to load a single AIS_localsl.nc file, which does not exist for wf1f. No fallback existed to sum the two sub-component files.

Fix
Added WORKFLOW_COMPONENT_FALLBACK_SUM config and compute_quantiles_sum() function to sum raw ensemble arrays from EAIS and WAIS before computing quantiles. The fallback is used in precompute_all() when the primary combined file is missing.

Fixed in
Commit 881e5e3

[Ttheegela]

Fixed in commit 881e5e3 wf1f does not produce a combined AIS_localsl.nc file; only EAIS_localsl.nc and WAIS_localsl.nc exist. Added WORKFLOW_COMPONENT_FALLBACK_SUM config and compute_quantiles_sum() function to sum the raw ensemble arrays from both sub-files before computing quantiles. precompute_all() now uses this fallback automatically when the primary combined file is missing.