feat: show time left, elapsed and estimated finish in status

[ynezz]

hi, my clankers found this nice project during research, I liked it so decided to make you aware about the changes I've made for my use cases, so everyone can profit from that, but feel free to close it or implement it differently, happy to help with testing, cheers, Petr

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prusactl status showed the progress of a running print, but not when the print ends. PrusaLink and Prusa Connect both report time_remaining and time_printing in seconds. The status line now adds the time left, the finish time on the local clock, and the time elapsed:

PRINTING 42%, 1h53m left (ends ~09:12), 1h30m elapsed, nozzle 255.1/255°C, bed 85/85°C

get_printer and list_printers gain time_elapsed and ends_at (RFC 3339) next to time_remaining. The new internal/jobtime package reads the fields once, for the CLI and for the MCP summary. Both leave out the same bad values: a value that is missing, negative or not a number.

Compatibility: time_remaining and time_elapsed are whole seconds.

Testing

• go test ./..., go vet, gofmt.
• Live on a CORE One L (firmware 6.8.1), on the Connect route and on the direct PrusaLink route, during real prints.

[trevin-lee]

Hi Petr, thanks for these. I'd tabled prusactl as bug-fixes-only, but with someone interested in it I'm reopening it for features.

I reviewed all five. This one is clean and I'm merging it. The only change is a rebase: CHANGELOG.md conflicts with the Unreleased section on main. I'll push that.

Your branches have maintainer edits on, so for the others I'll push the small fixes onto each branch and note what I changed in the PR. If you'd rather do them yourself, say so and I'll post the list instead.