fix(workspace): move detail Back into the header and drop the rail brand (#1789)

docs/architecture/embedded-inline-playback.md

@@ -162,8 +162,9 @@ Contracts:
   player subtree, so shell state changes cannot recreate the `<video>`.
 - **External MPV/VLC sessions do not flip the layout to watch** — browse
   layout stays, and the primary CTA keeps its "Stop <player>" behavior.
-- The shell's sticky arrow emits the host-owned `backClicked` in browse and
-  watch alike (unless `backAvailable=false`, when it is not rendered at all):
+- The shell's Back, rendered by the workspace header, emits the host-owned
+  `backClicked` in browse and watch alike (unless `backAvailable=false`, when
+  the shell registers none):
   hosts wire it to their route-level `goBack()`, straight back to the list —
   everything browse offers is also visible in watch, so a two-step unwind
   would be ceremony. Escape alone unwinds one level: in watch it emits
@@ -174,7 +175,7 @@ Contracts:
   [Portal Detail Navigation](./portal-detail-navigation.md).
 - The now-playing bar has one exit of its own: the "Close player" button
   emits `closed` and returns to browse without navigating. It carries no back
-  arrow — a second arrow beside the sticky one, with a different meaning,
+  arrow — a second arrow beside the header's, with a different meaning,
   was the duplicate this contract removes.
 - Entering watch scrolls the shell to the top; leaving keeps the scroll
   position.

docs/architecture/iptvnator-ui-guidelines.md

@@ -644,8 +644,8 @@ partial so Xtream and Stalker share the same behavior.
 
 The season header's actions wrap onto their own row, starting under the
 "Seasons and Episodes" heading, before the heading itself would wrap. The
-detail pane is narrower than the window (context panel, the sticky Back lane),
-so the header's own width decides, not a viewport breakpoint. A translation
+detail pane is narrower than the window (rail and context panel), so the
+header's own width decides, not a viewport breakpoint. A translation
 wider than the pane itself wraps rather than ellipsizing: unlike a fixed-height
 panel title, a content heading has room to wrap and should not lose words.
 

docs/architecture/portal-detail-navigation.md

@@ -23,30 +23,29 @@ do not reach global player shortcuts. Descendant controls retain their native
 keys and Tab order. Entering watch still scrolls to the top; Back and saved
 catalog scroll positions retain the existing navigation contract below.
 
-The shell owns a single sticky Back control, outside the collapsing hero. Its
-zero-height wrapper is a direct child of the scroll owner, so the control stays
-16 px from the top throughout long episode lists without shifting the hero.
-The button has an opaque app-themed surface, visible keyboard focus, an Escape
-shortcut hint via native `title` and Electron `no-drag` hit testing. The hint
-does not create an overlay that could consume the first Escape press.
+The shell owns the page's Back action, but the workspace header renders it.
+While `backAvailable()` is true, the shell registers a target with
+`WorkspaceBackNavigationService` (`@iptvnator/portal/shared/data-access`). The
+target, the `WorkspaceBackTarget` contract in `@iptvnator/portal/shared/util`,
+carries a label (the host's `backLabel`, else the translated "Back"), whether
+Escape currently runs it, and `run()`, which emits `backClicked`. The service
+keeps a stack in which the newest registration wins, and each release removes
+only its own target. A loading shell replaced by the loaded one therefore
+cannot clear its successor, whichever is destroyed first. The header shows the target as an `arrow_back`
+icon button in its leading slot (`data-test-id="workspace-header-back"`), to
+the right of the macOS traffic lights. That is where desktop apps and Material's
+top app bar keep navigation. The header never scrolls, so the control stays
+visible over long episode lists, and nothing floats over the scroll owner:
+detail columns keep symmetric insets and their full width. The button has
+Electron `no-drag` hit testing. In browse its tooltip and `aria-keyshortcuts`
+advertise Escape, and an Escape pressed on the focused button runs Back
+itself, because the shell's browse Escape requires focus inside the page. At
+≤640 px Back takes the context drawer toggle's slot (one navigation icon); the
+list it returns to shows the toggle again. This replaced #1763's 72 px lane
+reserved beside a sticky in-page arrow, along with its phone bar. Electron E2E
+`detail-header-back.e2e.ts` covers 1280, 780 and 375 px in browse and watch.
 
-The control floats, so the content makes room for it: while it is shown, every
-content column (hero content, watch-state player, episodes, About and extras)
-starts after a 72 px lane — 16 px inset, 40 px button, 16 px gap — and no scroll
-position puts the arrow over a heading or the player. The shell derives the lane
-from the button's geometry and publishes it as `--detail-back-lane`, which
-`content-hero` and `content-about` read too; hosts with `backAvailable=false`
-keep their own inset. The lane is horizontal because watch state is short of
-height, not width. A pane narrower than 400 px is the exception — a phone, or a
-desktop pane beside the context panel — because a 72 px column there would clip
-the player's controls. The pane decides, not the viewport: a `ResizeObserver`
-on the shell's border box (scrollbar-independent) sets `shell-host--compact`,
-and the wrapper becomes an in-flow 56 px sticky bar on `--app-header-bg` that
-content scrolls beneath and that takes the taps over it. Electron E2E
-(`detail-back-lane.e2e.ts`) sweeps both states with the lane at 1280 and
-780 px and with the bar at 700 and 375 px.
-
-The sticky control is route-level Back in both states: it emits `backClicked`
+The header Back is route-level in both states: it emits `backClicked`
 whether or not inline playback is active, so the arrow keeps one meaning and
 the list is one click away while watching. Only Escape unwinds one level: watch
 emits `closePlayerRequested`, browse emits `backClicked`. Hosts retain their
@@ -61,13 +60,13 @@ Escape bubbles through the shell before Material's body-level tooltip dispatcher
 so focused detail actions return with one press even while their tooltip is open.
 The document listener remains the outside-shell watch fallback; `defaultPrevented`
 prevents duplicate actions and preserves descendant handlers' priority.
-After Escape closes a player, lost focus moves to the sticky control (or the
-shell when there is no browse Back), without scrolling or stealing existing
-focus.
+After Escape closes a player, lost focus moves to the shell itself, without
+scrolling or stealing existing focus, so the next Escape and the scroll keys
+keep working on the page.
 
 Hosts without browse navigation set `backAvailable=false`: M3U uses its channel
 sidebar, and collection bootstrap placeholders have no return handler. They
-render no sticky arrow in either state and have no browse Escape action; their
+register no header Back in either state and have no browse Escape action; their
 watch exits are the bar's Close player button and Escape. Loading/error shells
 with a return handler keep Back available.
 
@@ -77,8 +76,8 @@ with a return handler keep Back available.
 - Stalker uses an inline/store-state detail model.
 - Detail pages themselves are two-state (browse ↔ watch) inside
   `PortalDetailShellComponent`; entering/leaving watch is a layout state,
-  not a navigation. Route-level back semantics are unchanged; the one
-  sticky arrow returns to the list from either state, while Escape and the
+  not a navigation. Route-level back semantics are unchanged; the header's
+  one Back arrow returns to the list from either state, while Escape and the
   now-playing bar's Close button close the inline player. See
   [Embedded Inline Playback](./embedded-inline-playback.md).
 - Favorites and recently viewed collections now use collection-owned inline detail

docs/architecture/workspace-shell.md

@@ -90,12 +90,18 @@ The shell is intentionally split into four persistent regions:
        because its data source is the SQLite worker bridge.
     2. Provider-aware context links derived from the active or current playlist.
     3. Settings remains a persistent footer shortcut in the rail.
+    4. No brand mark: it only repeated the first workspace link (Dashboard,
+       or Sources when the dashboard is off).
 2. Top header:
-    1. Playlist switcher.
-    2. Route-aware search input and command palette trigger.
-    3. Add source action.
-    4. Optional playlist refresh and route-specific shortcut actions.
-    5. Downloads shortcut in Electron.
+    1. Leading Back slot, shown while the current page registers a target
+       with `WorkspaceBackNavigationService` (detail pages today). At
+       ≤640 px it takes the context drawer toggle's place. See
+       [Portal Detail Navigation](./portal-detail-navigation.md).
+    2. Playlist switcher.
+    3. Route-aware search input and command palette trigger.
+    4. Add source action.
+    5. Optional playlist refresh and route-specific shortcut actions.
+    6. Downloads shortcut in Electron.
 3. Main body:
     1. Optional left context panel.
     2. Main router outlet content.