feat(devices): joined Totals by machine report

[iamtoruk]

Reworks codeburn devices into a spacious joined report that matches the requested ccusage-style layout: one row per machine plus a bold Combined row.

Columns: Host / Cost / Total tokens / Input / Output / Cache create / Cache read, all as full comma-grouped numbers in a roomy box table.

Totals by machine
┌──────────────────────┬─────────────┬─────────────────┬───────────────┬──────────────┬────────────────┬─────────────────┐
│  Host                │       Cost  │   Total tokens  │        Input  │      Output  │  Cache create  │     Cache read  │
├──────────────────────┼─────────────┼─────────────────┼───────────────┼──────────────┼────────────────┼─────────────────┤
│  ben-mbp (this Mac)  │  $6,751.84  │  3,001,779,631  │  202,286,956  │  14,487,808  │    45,687,883  │  2,739,316,984  │
│  ben-mm              │  $2,346.65  │    896,429,789  │  111,488,977  │   4,591,631  │     3,448,991  │    776,900,190  │
│  Combined            │  $9,098.49  │  3,898,209,420  │  313,775,933  │  19,079,439  │    49,136,874  │  3,516,217,174  │
└──────────────────────┴─────────────┴─────────────────┴───────────────┴──────────────┴────────────────┴─────────────────┘

Cache create = tokens written to cache, Cache read = tokens read from cache (summed from each device's daily history). Unreachable devices show their error in place of the numbers. Adds a small reusable box-table renderer (src/text-table.ts). Host tests + full suite pass; tsc clean.

Follow-up if wanted: the per-day cross-machine table (the second screenshot) needs per-day provider data the shared payload does not currently carry.