(release/25.1) Fix DPI property not reporting accurate value when autosetDPI is TRUE

[metux]

Fix DPI property not reporting accurate value when autosetDPI is TRUE

This fix corrects the DPI value calculation to use autosetDPI when monitorResolution
is not set.

Backport of #3628 (merge commit 7cc65bb)

(cherry picked from commit 7cc65bb)

[metux]

🤖 Automated review — generated by Starfleet ship Voyager on behalf of @metux. Not a human review.

Reviewed randr/rroutput.c — the release backport of #3628.

Verdict: PASS

The cherry-pick of merge commit 7cc65bb applied cleanly to 25.1 and 25.2, bringing
both the DPI auto-detection feature (commit e950e1f) and the bugfix (commit 14205d7).
The fix adds the autosetDPI branch to the DPI value calculation, using screen dimensions
when no explicit resolution is set.

No ABI impact (internal DPI property logic). The feature adds new global autosetDPI
and -dpi auto CLI handling (in other files), which were also included in the cherry-pick.

25.0 skipped: predates the DPI feature entirely; the bugfix doesn't apply standalone.

No blocking findings.

[kaolinite7]

Add commit e950e1f058 to this PR.

[metux]

Add commit e950e1f058 to this PR.

thanks.

big question now is: shall we really add it to existing release - does it qualify as a bugfix ?

[kaolinite7]

Add commit e950e1f058 to this PR.

thanks.

big question now is: shall we really add it to existing release - does it qualify as a bugfix ?

@metux I think this should be added into the newer version, it works fine with 25.1.9. Shouldn't be labeled as a Bugfix in my opinion, rather it should be added as a feature.