Merge p9-w8-8e-add-track-buttons into dev (8.E: medium-aware Add Track on Release Archive tabs)

DeepDrftManager/Components/Pages/Tracks/BatchUpload.razor

@@ -130,6 +130,25 @@
     private ReleaseType _releaseType = ReleaseType.Single;
     private ReleaseMedium _medium = ReleaseMedium.Cut;
 
+    // Optional pre-select from the Add-Track buttons (§8.E): /tracks/upload?medium=session lands the
+    // form already in Session mode. A seed only — the medium selector stays user-changeable after load.
+    // Unrecognised/absent values fall through to the Cut default (same defensive posture as the API's
+    // TrackController.UploadTrack medium parse).
+    [SupplyParameterFromQuery(Name = "medium")] public string? MediumParam { get; set; }
+
+    protected override void OnInitialized()
+    {
+        // Seed the medium from the query param so a pre-selected upload form (e.g. the Sessions tab's
+        // Add Track) lands already showing that medium's conditional fields. Goes through OnMediumChanged
+        // so the single-track collapse runs identically to a user selector change.
+        if (!string.IsNullOrWhiteSpace(MediumParam)
+            && Enum.TryParse<ReleaseMedium>(MediumParam, ignoreCase: true, out var medium)
+            && Enum.IsDefined(medium))
+        {
+            OnMediumChanged(medium);
+        }
+    }
+
     // Switching to a single-track medium collapses any multi-track selection to the first row so the
     // single-track invariant holds before submit. The predicate reads the same MediumRules cardinality
     // declaration the upload service enforces, so the form and the domain cannot drift.

DeepDrftManager/Components/Pages/Tracks/TrackList.razor

@@ -61,7 +61,21 @@
            The medium tabs are enum-driven — a fourth medium adds a tab automatically; only a label-lookup
            entry (MediumTabLabels) and a content arm (MediumGrid) are needed, no markup fork. Selecting a
            tab swaps the grid below in place; no navigation to a separate page occurs. *@
-        <MudTabs Elevation="0" Rounded="true" ApplyEffectsToContainer="true" PanelClass="pt-4">
+        @* Medium-aware Add Track (§8.E): the button lives in the tab-strip chrome (not inside any grid
+           component — 8.C owns those) and reflects the active tab. It pre-selects the upload form to the
+           tab's medium via a single query-param (?medium=…); the ALL tab defaults to Cut. The medium is a
+           seed only — the upload form's selector stays user-changeable after landing. *@
+        <MudStack Row="true" Justify="Justify.FlexEnd" Class="mb-2">
+            <MudButton Variant="Variant.Filled"
+                       Color="Color.Primary"
+                       StartIcon="@Icons.Material.Filled.Add"
+                       Href="@AddTrackHref(ActiveMedium)">
+                Add Track
+            </MudButton>
+        </MudStack>
+
+        <MudTabs Elevation="0" Rounded="true" ApplyEffectsToContainer="true" PanelClass="pt-4"
+                 @bind-ActivePanelIndex="_activeTabIndex">
             <MudTabPanel Text="ALL">
                 <CmsAllReleasesGrid OnReleasesChanged="OnAlbumsChanged" />
             </MudTabPanel>
@@ -87,6 +101,21 @@
 @code {
     private CmsTrackGrid? _grid;
 
+    // Active Release-Archive tab. Panel 0 is ALL; panels 1.. map to Enum.GetValues<ReleaseMedium>() in
+    // order. Drives the medium-aware Add Track button (§8.E).
+    private int _activeTabIndex;
+
+    // The medium the Add Track button pre-selects for the active tab. ALL (panel 0) defaults to Cut
+    // (Daniel, 2026-06-13); each medium tab maps to its enum value by position, so a fourth medium tab
+    // gets a correct Add Track for free — no markup fork.
+    private ReleaseMedium ActiveMedium =>
+        _activeTabIndex <= 0 ? ReleaseMedium.Cut : Enum.GetValues<ReleaseMedium>()[_activeTabIndex - 1];
+
+    // Single query-param convention: the upload page reads ?medium=… and seeds its selector (which stays
+    // user-changeable). Always explicit, including ALL→cut, so the link is unambiguous.
+    private static string AddTrackHref(ReleaseMedium medium) =>
+        $"/tracks/upload?medium={medium.ToString().ToLowerInvariant()}";
+
     // Medium → tab label. The one place medium display text lives for the tab strip; a future medium adds
     // one entry here and surfaces a tab automatically. Mirrors the extension discipline the retired
     // ReleaseArchiveBrowser used for its cards. The ALL tab is rendered separately (it is not a medium).