Expose Lifetime in CLI dashboard

[0monish]

Note: This PR is part of a reviewer-friendly split of the original PR #391 (24 files). The monolithic PR was split into three surface-specific PRs: CLI/dashboard (this PR), macOS menubar, and GNOME extension.

Summary

• expose lifetime as a first-class CLI/dashboard period in the interactive report flow
• keep CLI/dashboard all aligned with the existing 6-month aggregate instead of turning Lifetime into a settings-only replacement
• add regression coverage for Lifetime date ranges and for older sessions appearing under --period lifetime

Files Changed

• README.md — add lifetime CLI docs and update dashboard shortcuts
• src/cli-date.ts — add lifetime period type and date range logic
• src/daily-cache.ts — update cache retention comment for lifetime semantics
• src/dashboard.tsx — add lifetime to dashboard period picker (key 6) and rendering logic
• src/main.ts — add lifetime period support to report/optimize/compare/models/yield commands, plus menubar JSON generation
• tests/cli-date.test.ts — add lifetime period round-trip and date range tests
• tests/cli-json-daily.test.ts — add lifetime period regression test for older sessions beyond 6-month cache window

Period Semantics

• all remains the bounded Last 6 months period.
• lifetime is the uncapped all-time period.
• The two periods are intentionally different, not contradictory.

Testing

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

Screenshot / Terminal Output

Surface	State	Before	After
CLI / dashboard	Lifetime-selected dashboard

Related issue: #389

[ozymandiashh]

Thanks — splitting the original #391 into surface-specific PRs was the right move, and a first-class lifetime period is a reasonable ask.

Status: needs a rebase before review/merge — it currently conflicts with main. This PR's base is from 2026-05-27, and the CLI/dashboard surface it touches has been reworked substantially since:

• src/dashboard.tsx, src/cli-date.ts, src/daily-cache.ts, src/main.ts — e.g. #533/#534 (usage-by-device + in-dashboard discovery), #573 (instant dashboard load, default to today), #582 (mobile-responsive web dashboard), #592 (per-session context token tree across CLI/TUI/dashboard).

It's not superseded — lifetime is still absent as a period on main — but the plumbing (period parsing in cli-date.ts, the daily-cache window, and the dashboard.tsx period UI) has moved enough that the change needs to be re-applied against the current code rather than merged as-is.

Before a full review:

1. Rebase onto current main and re-wire the lifetime period through the current cli-date.ts / daily-cache.ts / dashboard.tsx.
2. Confirm this still coordinates with the sibling menubar/GNOME PRs from the #391 split (period names/semantics consistent across surfaces).
3. Refresh tests/cli-date.test.ts / tests/cli-json-daily.test.ts against the rebased behavior.

Once it's rebased and CI is green I'll do the full adversarial pass. Thanks for keeping the split reviewer-friendly.