HUD and connect screen, second pass

At 331 of 1500 health the bar read as nearly full. The pack's bar sprite
is light all the way through, so the EMPTY part was the brightest thing
on it. Every bar now has a dark track inside its frame, scaled with the
bar's height -- a fixed inset left the thin experience bar four pixels of
track and six of white -- so empty reads as empty.

Health carries its number inside the bar, and a damage trail: the part
the last hit took stays in a darker red for a moment and then drains, so
a hit reads as an amount rather than as a bar that is suddenly shorter.
Two quick hits read as one, measured from where the first began. The
trail was pale at first and the number vanished against it; darker fixed
that. Experience flashes and shows "+N xp" on a kill, summed across a
burst so it does not flicker. Every block of HUD text sits on a dark
panel, since the floor art is busy enough to beat a text shadow.

Centre banners for the moments that change what you should do: a level
gained, a boss changing phase (not the phase it was found in), and the
escape channel -- which was a second bar in the corner and is now one
bar where you are looking, with the key to keep holding. Party members
you cannot see get a marker at the edge of sight pointing the way to
them. Empty inventory slots step back, so the blank parchment square is
no longer the most prominent thing in the row.

The connect screen opens on a real boss pattern behind its panel -- the
bosses' own emitters, fired into a pool and drawn by the game's own bullet
renderer, dimmed. It is primed with five seconds of ticks: every pattern
starts at the centre of the screen, which is where the panel is, so
unprimed it showed nothing for its first second or two. The title is
spaced and underlined, Credits is on the screen itself, Join says Enter
works and has focus, the port is validated before it can fail, and
"connecting" animates so a slow attempt does not look frozen.

The boss-bar logic is pulled out into track_boss() so it can be tested:
it waits for the fog to light the boss, stays for the fight, has to be
seen again in the next dungeon -- every dungeon's boss is actor 1, so the
id alone would have carried "seen" across -- and announces only real
phase changes. screenshot.tscn captures the escape banner by progress
rather than by frame count, because the channel is server ticks and a
completed escape teleports the player out mid-sequence.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/unit/test_hud.gd.uid

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