[gui] The K1 combat HUD text scale is absolute, not compounded

[MichaelMoroz]

The defect

The K1 combat sequence HUD's text grows with every level load, doubling each
time, until it wraps and clips.

Cause

HUD::onGUILoaded scales by reading the control's own scale back:

control->setScale(control->scale() * kK1CombatTextScale);

That is a read-modify-write on state the wrapper does not own. The HUD wrapper
is reconstructed on loadgame, reset and new-session, but the control tree it
binds lives in the GUI cache and survives — so each reconstruction multiplies
the previous result again.

An ordinary warp preserves the wrapper and shows nothing, which is why this
presents as a level-load bug rather than a HUD one, and why it is easy to miss
when testing by warping.

Fix

Derive the value from the live layout and text inputs, so applying it to an
already-scaled tree is idempotent. The wrapper and the control tree have
different lifetimes; the operation should not care which one it is looking at.

Measurement

Three loadgame cycles, glyph region of the combat text:

load	before	after
1	1203 px, 314x14	1203 px, 314x14
2	5207 px, 629x28	1203 px, 314x14
3	22770 px, clipped	1203 px, 314x14

After the fix the first and third regions are pixel-identical.

Note on verification

The measurements above were taken on a downstream branch that carries this file
unchanged from master — the block is byte-identical here, and the patch
applies to master as-is. I have not built master itself, so a CI run is
worth having before merge.

[modawan]

Good catch. Thank you!