feat(learn,todo,train,meditate,ui): the navigation bar flush with the foot, a fade above it

Below medium windows the frame's bar is Material 3 Expressive's again,
flush with the window's foot (decided 7 Nov 2026 by the developer): the
theme's NavigationBar across the whole width, 64 dp in its own colour,
running on beneath the system's bar as Material's does. Right above it a
fade 32 dp high, from the background of the screen in view (the
ScreenTint's, the theme's surface before a screen claims one) made
see-through to that background, so what scrolls on beneath the bar fades
out rather than being cut off; taps pass through it. The rail of wider
windows stays as it was.

halkyon_ui's FloatingNavigationBar becomes FlushNavigationBar, its side
margin, lift and rounded card gone. Its coverOf is now the whole room
content leaves at its end, the system's bar included (the body's bottom
padding: bar, fade and system's bar inside the frame, the system's bar
alone outside it), and floating buttons rise by buttonLiftOf, the same
without the system's bar, which a Scaffold keeps them clear of itself.
Lists, Todo's hour grid and the Plan's sheet keep using coverOf; the
Profile's list no longer adds the system's bar a second time.

Whats-New: The navigation bar sits at the bottom edge again, with a soft fade above it.
Whats-New-De: Die Navigationsleiste sitzt wieder am unteren Rand, mit einem sanften Übergang darüber.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

docs/adr/0030-halkyon-train.md

@@ -1485,7 +1485,12 @@ Strava. What was found, 27 Oct:
   where the device doesn't record (the desktop), which keeps the plans beside the days
   in Profile. The frame is Learn's, moved into halkyon_ui for every app
   (`NavigationFrame`, `TabsStack`): a rail with the app's icon on top from medium
-  windows on, a bar floating above the foot below, a tick on every choice. Driven by
+  windows on, a bar floating above the foot below, a tick on every choice (amended 7 Nov
+  2026, the developer's decision: the bar is flush with the foot, as Material 3 Expressive
+  keeps it, 64 dp in the theme's own colour across the whole width, and a fade 32 dp high
+  into the background of the screen in view above it replaces the floating card, so what
+  scrolls on beneath it fades out rather than being cut off; halkyon_ui's
+  `FlushNavigationBar`, the rail unchanged). Driven by
   go_router as Learn's (a `StatefulShellRoute`, each tab keeping its own stack): a
   workout's page opens in Home and a day's in Profile with the tabs beside them, the
   route and plan editors and the recording over them; over keeping `Navigator.push`
@@ -1607,7 +1612,7 @@ Strava. What was found, 27 Oct:
     expanded windows on, the map and the rest side by side (a 400 px pane, Material's
     supporting pane, as the Maps tab's list and map, D60). Without a track or without
     the map, the rest alone, as before. The page stays in Home (back leads there) but
-    opens on the root navigator, over the shell, so without the floating bar (D60 had
+    opens on the root navigator, over the shell, so without the navigation bar (D60 had
     it run on beneath the bar).
   - **What the map's source sees** ("Map by OpenFreeMap: it sees…", and the link to what
     it keeps) moves behind halkyon_ui's question mark (`HelpButton`, which gained an

docs/adr/0033-halkyon-todo.md

@@ -48,7 +48,8 @@ the rail, a wash of strawberry, settings grouped as theirs. What the screenshots
 
 - **D1 Todo's frame is Train's (ADR 0030, D60)**: go_router with a `StatefulShellRoute`,
   every tab keeping its own stack; halkyon_ui's `NavigationFrame`, a bar floating above the
-  foot below medium windows and a rail with Todo's icon on top from medium on, a tick on
+  foot below medium windows (flush with it, a fade above it, since 7 Nov 2026: ADR 0030,
+  D60's amendment) and a rail with Todo's icon on top from medium on, a tick on
   every choice; Todo's account sheet goes. Over a frame of Todo's own, which would make the
   three apps behave differently on the same window.
 - **D2 Four tabs: Today, Upcoming, Inbox, Browse** (recommended, over Todoist's five and over
@@ -553,7 +554,7 @@ The developer's review of 4 Nov 2026, again beside Todoist's screens.
   hidden as the person last left it, remembered with the settings (`TodayView.plan`,
   open at first); **on a phone, a sheet over the day's foot** (the developer's choice,
   over the Plan on wide windows alone and over a strip of tasks above the day), half
-  the body high above the floating bar, closed until asked and while the app runs;
+  the body high above the navigation bar, closed until asked and while the app runs;
   a row held there **lowers the sheet to its heading**, the day free behind it, and it
   rises again once the row is dropped. The sheet is part of Today's screen, not a
   modal route (agent's choice): a modal sheet's barrier would take the drop meant for

docs/adr/0038-halkyon-meditate.md

@@ -42,7 +42,8 @@ names and pictures are its own). Everything below is Halkyon's own.
 
 - **D1 Meditate's frame is Todo's and Train's** (ADR 0033, D1; ADR 0030, D60): go_router
   with a `StatefulShellRoute`, each tab keeping its own stack, halkyon_ui's
-  `NavigationFrame` (the bar floating above the foot below medium windows, a rail with
+  `NavigationFrame` (the bar below medium windows, floating above the foot at first and
+  flush with it, a fade above it, since 7 Nov 2026 (ADR 0030, D60's amendment), a rail with
   Meditate's icon on top from medium on), halkyon_app's first start, sign-in and
   account, What's new after an update, About, English and German. Copied from Todo's
   and renamed, as Train's was (ADR 0030, D12), Todo's own features left out.