docs(centralui): template picker on Create Instance, New Instance… from the Templates tree

Claude-Session: https://claude.ai/code/session_01G2GHPnbbKGvyyfbr2XBRVH

docs/plans/2026-08-21-create-instance-bindings-design.md

@@ -42,8 +42,12 @@ Same `FlattenSession` memo, so it is one template-chain walk per call.
 
 ### 3.2 Create page (CentralUI `InstanceCreate.razor` + new code-behind)
 
+- **Superseded 2026-08-21 (`docs/plans/2026-08-21-template-picker.md`):** the Template `<select>`
+  described below is now a read-only folder-path field + `TemplatePickerDialog`, and the page takes
+  a `?templateId=` query preselect (what the Templates tree's "New Instance…" navigates with). The
+  card's trigger is unchanged — a pick still calls `OnTemplateOrSiteChangedAsync()`.
 - The **Connection Bindings** card appears once Template *and* Site are set; changing either
-  re-runs the preview (debounced by the select's change event — no typing involved) and resets
+  re-runs the preview (a pick or a site-select change — no typing involved) and resets
   the card. Rows = `PreviewAsync(...).Attributes.Where(DefaultDataSourceReference ?? DataSourceReference != null)`
   → `BindingRow(canonicalName, default, null, null)` → `BindingGroupBuilder.Build(rows, siteConnectionIds)`.
 - **Group rows** are the Configure page's group-header row (connection select, Object input,

docs/plans/2026-08-21-template-picker-design.md

@@ -1,6 +1,6 @@
 # Template picker for Create Instance + "New Instance…" from the Templates tree (design)
 
-**Date:** 2026-08-21 · **Status:** designed — plan `docs/plans/2026-08-21-template-picker.md`
+**Date:** 2026-08-21 · **Status:** **implemented** 2026-08-21 — plan `docs/plans/2026-08-21-template-picker.md`
 **Mockup:** Claude artifact "Template Picker" (https://claude.ai/code/artifact/71fea4e0-eafc-4b84-8157-66b450126330)
 **Builds on:** `docs/plans/2026-08-21-create-instance-bindings-design.md` (the create page this changes), the shared `TemplateFolderTree` (Templates page, Transport export wizard)
 

docs/plans/2026-08-21-template-picker.md.tasks.json

@@ -23,7 +23,7 @@
     {
       "id": 4,
       "subject": "Task 4: Create page \u2014 picker field + ?templateId= preselect",
-      "status": "pending",
+      "status": "completed",
       "blockedBy": [
         3
       ]
@@ -31,12 +31,12 @@
     {
       "id": 5,
       "subject": "Task 5: Templates page \u2014 New Instance\u2026 menu item (Deployer-gated)",
-      "status": "pending"
+      "status": "completed"
     },
     {
       "id": 6,
       "subject": "Task 6: Pin the Topology Disable confirm label",
-      "status": "pending"
+      "status": "completed"
     },
     {
       "id": 7,