A single dense table of every (provider, model) you have used in the
selected period, sorted by cost. Inspired by tokscale's per-model
output and ccusage's responsive cli-table3 layout, ported to plain
Node with no new runtime dependency.

Default view: one row per (provider, model) with a Top Task cell
showing the dominant task category and its cost share, e.g.
`Coding (42%)`.

`--by-task` explodes each model into one row per task type, with
provider/model cells blanked on subsequent rows of the same group
and a horizontal divider between groups so the sections read as
distinct units.

Output formats: table (Unicode box-drawn, default), markdown
(GitHub-flavored, copy-paste friendly), json, csv.

Filters: --period (today/week/30days/month/all, default 30days),
--from/--to, --provider, --task, --top, --min-cost, --no-totals.

The table renderer auto-sizes every column to its content (no fixed
widths leaving trailing whitespace) and drops cache columns as a
pair when the terminal is narrow, then input/output, then top-task,
in that order. Provider, model, total, and cost stay regardless.
Visible-width math uses strip-ansi (already a dependency) so styled
cells pad correctly. Cyan headers, yellow totals, dim provider name.

The aggregator walks every parsed turn and attributes each
assistant call to its (provider, model, task) bucket, computing
real input / output / cache_write / cache_read tokens and cost.
Output tokens include reasoning. Cached input tokens are folded
into cache_read so the column matches what users intuitively expect.

19 fixture-based tests cover aggregation correctness, byTask
grouping, taskFilter, topN/minCost filters, reasoning-as-output,
all four renderers (table/markdown/json/csv), narrow-terminal
column dropping, CSV/markdown escaping, totals row toggle, and
visible-width math under styled cells.