re: the title menu wraps -- Q5 measured, Q4 driven, and one of my own

method lines withdrawn

Q5, measured off two boots: up/down move one item and WRAP at both ends
on the 5-item main menu and the 3-item EXTRAS alike; left/right do
nothing; B goes up one level and restores focus to the item you came
from (4/4); B on the main menu returns to the title; B on the title does
nothing. The menu opens on TUTORIAL -- the middle item -- 2/2, though a
third recorded run implies NEW GAME, so that one is reproducible rather
than invariant and says so.

Q4 by driving: LOAD GAME opens the save-slot list, TUTORIAL the lesson
list, OPTIONS the settings menu, EXTRAS build 6, MISSION SELECT the stage
list. NEW GAME is not tested -- A on it hangs the emulator and this
iteration needed the session. The GamePart ID behind each is NOT
measured: it is the entry of the decoded id table whose name matches the
screen I saw, and the page says so rather than wearing the badge.

And the withdrawal. Last iteration I wrote that these menus drop d-pad
presses shorter than ~0.3s. They do not. Once wrap is measured, every
press count I had is exactly right -- four presses moved four steps
THROUGH the bottom, which lands one above where a non-wrapping menu
would. I invented hardware flakiness instead of testing the ends of the
list. METHOD keeps the withdrawal rather than deleting the line.

Also: label brightness is not a cursor oracle here -- the background art
outshines the highlight on some rows. menu_focus.py reads the focus ring
instead, 254 vs <82, no tuning.

docs/port/HANDOFF.md

@@ -30,8 +30,8 @@ authored version can be deleted.
 | Q1 | keyframe time unit + ramp shape | ✅ answered | ramp is **linear**; the clock advances **2 units per rendered frame**; working conversion **1 unit = 1/60 s** — [`ui-keyframe-time-unit.md`](../re/ui-keyframe-time-unit.md) |
 | Q2 | which build is which screen state | ✅ answered | `GP_TITLE` is **8 screens shipped twice, EN/JP**: 4/7 title art, 2/3 the `PRESS Ⓐ` plate, 5/8 main menu, 6/9 `EXTRAS`, 0/1 and 10/11 two unidentified `DELTASABER` plates — [`ui-title-build-map.md`](../re/ui-title-build-map.md) |
 | Q3 | paint order for the six screens | ✅ answered | **decoded**: a `u16` layer key at `+0x0A` of each `T8aD` sprite header, stable-sorted with declaration index; unkeyed elements get an implied key. Confirmed on 5 measured orders + `EXTRAS` vs a capture. One residual: the **tie-break** is unknown and bites on one element of the title — [`structures/ui-paint-order-key.md`](../re/structures/ui-paint-order-key.md) |
-| Q4 | button → GamePart | ❔ open | labels are baked into sprites |
-| Q5 | navigation semantics | ❔ open | |
+| Q4 | button → GamePart | 🟡 mostly answered | **measured** which screen each button opens (4 of 5; `NEW GAME` untested — it hangs). The **GamePart id is a name match** onto the decoded id table, not a measurement — [`menu-navigation-semantics.md`](../re/menu-navigation-semantics.md) |
+| Q5 | navigation semantics | ✅ answered | **measured**: opens on `TUTORIAL` (not the top); ⬆⬇ one step, **wraps both ends**; ⬅➡ do nothing; Ⓑ returns to the parent **with focus restored**; Ⓑ on the main menu → title; Ⓑ on the title → nothing — [`menu-navigation-semantics.md`](../re/menu-navigation-semantics.md) |
 | Q6 | boot sequence + what drives it | 🟡 partial | order observed, and the **attract cycle is timed**: ~8–10 s idle on the title → fade to black → ~85 s of video → title again, plate and all. The driver is still not decoded |
 | Q7 | transitions | ❔ open | |
 | Q8 | menu audio bindings | ❔ open | cue table complete, event binding is not |
@@ -94,6 +94,20 @@ authored version can be deleted.
   blend of **one element on one screen** (a title glow). Take the stable sort and
   accept that.
 
+* **Menu movement, measured off the running game.** ⬆⬇ move one item per press
+  and **wrap at both ends** (5-item main menu and 3-item `EXTRAS` both). ⬅➡ do
+  nothing. Ⓑ goes up one level **and restores focus to the item you came from**;
+  Ⓑ on the main menu returns to the title; Ⓑ on the title does nothing. The main
+  menu opens focused on **`TUTORIAL`**, the middle item — 🟡 reproducible in this
+  harness (2/2) but a third recorded run implies `NEW GAME`, so re-test before
+  hardcoding it. All **measured**, none of it on the disc.
+* **Each button's destination is measured; its GamePart id is not.**
+  `LOAD GAME` → the save-slot list, `TUTORIAL` → the lesson list, `OPTIONS` →
+  the settings menu, `EXTRAS` → `GP_TITLE` build 6, `EXTRAS ▸ MISSION SELECT` →
+  the stage list. ❔ `NEW GAME` is untested — Ⓐ on it hangs the emulator. The
+  GamePart ids (`3`, `25`, `8`, `5`, `7`) are the entries of the decoded id table
+  whose **names match the screens seen**; that binding is authored, not measured.
+
 * **The GamePart id table** — 29 entries at `.rdata 0x820A1630`, confirmed by the
   executable's own registration strings. ✅ This is the screen vocabulary; which
   button reaches which entry is Q4 and is *not* part of it.