* Resolve Fireworks-hosted models to friendly display names
Fireworks fleet models arrive as `accounts/fireworks/models/<slug>` and
were leaking the raw path/slug in reports and the dashboard (e.g.
`fireworks/mode…`, `glm-5p2`). getShortModelName's path fallback now takes
the last path segment and re-resolves it, so a known slug earns a friendly
name (GLM-5.2, Qwen 3.7 Plus, Kimi K2.7 Code, DeepSeek v4 Pro/Flash) while
an unmapped slug still falls through to the raw segment.
Display-only: getModelCosts prices off the full id, so dollar amounts are
unchanged. The By Model dashboard panel now renders through getShortModelName
too, so already-cached raw keys normalize without a cache rebuild.
* Merge By Model rows that resolve to the same display name
Once path-style ids normalize, a mixed-vintage cache can hold more than one
raw key for the same model (the full accounts/fireworks/models/<slug> path
from an older build and the bare slug/friendly name from a newer one). The
dashboard By Model panel aggregated by raw id, so those rendered as duplicate
rows once both mapped to the same display name.
Extract the aggregation into a pure, tested aggregateModelTotals() keyed by the
resolved display name so the rows merge into one. This also aligns the panel
with modelEfficiency, which is already keyed by getShortModelName.
