fix(menubar): show a Total row under the Trend tooltip's model breakdown

[ozymandiashh]

Summary

• If only Claude is selected, hovering a Trend bar in the menubar popover used to show the day's cost in the tooltip header. Since 0.9.24 it shows a model breakdown and a token count instead, and the day's cost is gone from the tooltip. The web dashboard tooltip still ends with a Total row.
• The model rows are not new. What changed is the data behind the Claude-only view:
  • Up to 0.9.23, provider-filtered history.daily rows in src/usage-aggregator.ts set inputTokens/outputTokens to 0 and topModels to empty.
  • 38e6e19 (harden provider period and cache contracts, first shipped in 0.9.24) replaced that with overlayProviderDaySlices, which reads the real per-provider slices, so those rows now carry tokens and models.
  • TrendInsight switches the chart to tokens whenever any bar has tokens. With Claude selected, the chart switched from $ to tokens, and so did the BarTooltipCard header. The card never had a Total row, so the cost disappeared.
  • The model rows can't stand in for a total either: the payload carries up to 5 topModels and the card renders 4.
• What changed, in BarTooltipCard only:
  • When a day has a model breakdown, the rows now end with a 0.5pt separator and a Total row laid out like a model row: Total, the day's cost (bar.cost, shown when above 0, like the model rows) and N tok (bar.tokens, always shown, like the model rows).
  • The figures are the payload's day totals, not a sum of the visible rows.
  • The header figure now shows only on days without a breakdown, so no number appears twice. In the All view it moves from the header down to the Total row.
  • New "Total" key in en and zh-Hans (总计), plus a CHANGELOG entry under Unreleased > Fixed (menubar).
• What did not change:
  • The CLI and the payload. Carrying real per-provider tokens is correct; this only changes how the tooltip shows them.
  • How the chart picks its metric. The Claude-only chart still plots tokens.
  • Days without a model breakdown, which render exactly as before.
  • The web dashboard, desktop app and Windows tray. The hourly buckets and session breakdown mentioned in the issue exist only in the web dashboard; the menubar Trend chart is daily.

Fixes #1433

Testing

• I have tested this locally against real data (not just unit tests)
• npm test passes
• npm run build succeeds

This is a Swift-only change, so I didn't run the npm checks. I also haven't run the patched app against my own data. What I did run:

• swift build in mac/ passes, both incremental and from a clean build dir, with no warnings from HeatmapSection.swift.
• swift test can't run on this host (Command Line Tools only, no Testing module), so CI is the gate for the Swift tests.
• Localization: I wrote a script that copies the rules from LocalizationCatalogTests, LocalizationCoverageTests and LocalizationSourceScanner. It passes on main (619 keys) and on this branch (620 keys). I also compiled the repo's own LocalizationSourceScanner.swift against both trees. It finds 0 unrouted literals and picks up Total as a requested key. The new N tok text is covered by the scanner's tok exemption.
• Payload shape: I ran codeburn status --format menubar-json --period week with and without --provider claude. The Claude daily rows now have nonzero input/output tokens and a topModels list; the All rows have 3 to 5 topModels.
• Render harness: I copied BarTooltipCard verbatim from main and from this branch and rendered both with ImageRenderer at 332pt wide (popover width minus padding), at 2x, in light and dark:
  • All view with 5 models: the Total row shows the day's cost and tokens, and Total lines up with the model names.
  • Claude only: the day's cost is back in the tooltip, in the Total row.
  • Day with tokens but no cost: the Total row shows only tokens.
  • Day with no breakdown: the image is byte-identical to main in both light and dark.
  • Long model names, a 5-digit cost, a 1B+ token count and the zh-Hans label: nothing clips.
  • I can attach the before/after images.
• The card is about 19.5pt taller (one row plus the separator). Its bottom edge is pinned, so it now reaches further up into the chart and can cover a short hovered bar. I left the offset alone to keep the diff small.

[github-actions]

Closing for now: you already have 5 pull requests open (#1339, #1347, #1352, #1364, #1370), and we review at most 5 per contributor at a time. Reopen this one when one of them is merged or closed. Issues are always welcome.