Rework logbook entry directory path

[jmewes]

Currently the path for logbook entries looks like this:

/Users/jdoe/Examples/2026/01/07/20.04_this-is-just-a-test-with-some-rando

It could be shortened and clarified like this:

~/Examples/2026/01/07/20_04/this-is-just-a-test

The old and new path pattern should be supported in parallel.

[jmewes]

The timestamp directory might be left out to reduce the time needed to open the directory in the file explorer. In the search results, the logbook entry time might be inferred by the operating system file creation time.

[jmewes]

If the same name is used multiple times, the directory name should get a suffix with a counter, e.g.

log add "WIP"
=> 
.../2026/01/09/wip


log add "WIP"
=> 
.../2026/01/09/wip_2


log add "WIP"
=> 
.../2026/01/09/wip_3