Phase 5 is Aranos, not Veldin -- Veldin is not on this disc

Caught by the user, and it was wrong in four places: the Phase 5 heading, its
gate, its go/no-go line, and the PCSX2 verification plan's "Level 0 (Veldin)".

Veldin is Ratchet & Clank's home planet in the 2002 game. Going Commando opens on
Aranos, and there is no Veldin anywhere in this disc. The error looks like it
carried over from the first game when the roadmap was drafted, which is an easy
slip to make and an unhelpful one to leave standing: a vertical slice defined as
"completable and matching PCSX2 frame-for-frame" is not something anyone could
have attempted or judged while pointing at the wrong planet.

Confirmed against the vendored decomp rather than taken on faith. Its
docs/LEVELS.md refers to level 00 as Aranos directly -- "corrects three measured
Aranos entries before fingerprinting ... These corrections apply to level 00 only"
-- so level 0 is Aranos in the reference material this project has been using all
along, and the roadmap disagreed with the decomp.

There is a real R&C1 reference nearby and it is worth keeping, because the
reasoning under the gate is sound and only the noun was wrong. Phase 5 argues that
spherical gravity is the thing most likely to break, because it invalidates the
movement and camera assumptions the engine inherits from Ratchet & Clank (2002).
That is about inherited code from the previous game, not about the level being
built, and the text now says so explicitly so the next reader does not have to
work out which game is meant.

No code change. Documentation only.

docs/plan/pcsx2-verification.md

@@ -39,7 +39,7 @@ The comparison:
 
 ## Result: levels 0 and 1, verified 2026-10-11
 
-Level 0 (Veldin), three inputs -- the live emulator over PINE and two PCSX2
+Level 0 (Aranos), three inputs -- the live emulator over PINE and two PCSX2
 savestates from that level, all agreeing byte for byte:
 
 ```text