feat: dump subcommand

[suft]

Summary

Adds a daylog dump command that concatenates every log in a project, addressing #82.

• I went with a standalone dump subcommand instead
• Since it's project-wide rather than a variant of showing a single day's log
• It leaves room for its own flags (--reverse, --since, --until) without overloading show
• Happy to rename/restructure if a flag on show is preferred instead.

What's included

• daylog dump — concatenates all logs, oldest → newest by default.
• --reverse — newest → oldest instead.
• --since / --until — restrict the range to logs on or after / on or before a given date (inclusive on both ends)
• -o/--output — reuses the existing markdown/text output formatter, same as show.
• Respects -p/--project like the other commands.

Example usage

daylog dump
daylog dump -r
daylog dump --reverse
daylog dump -o text
daylog dump --since "1 week ago"
daylog dump --since 2023/01/07 --until yesterday
daylog dump -p work

Closes #82

[notnmeyer]

sorry for the delay! ill review this soon 👍