docs: clarify reorder + indent shortcuts in help and TUI reference

In-app help overlay now spells out that K/J auto-promotes at the parent
edge and that Shift+→ / Shift+← perform indent/outdent. The canonical
TUI reference (skills/agent-deck/references/tui-reference.md) gets the
same two clarifications. README itself is a curated subset and was
already pointing at the TUI reference for the full table.

Author: AdamiecRadek

internal/ui/help.go

@@ -245,8 +245,8 @@ func (h *HelpOverlay) View() string {
 				{previewKey, "Toggle preview mode (output/stats/both)"},
 				{unreadKey, "Mark unread"},
 				{quickApproveKey, "Quick approve (send '1' to Claude)"},
-				{reorderKeys, "Reorder up/down"},
-				{"Shift+→ / ←", "Indent / outdent (sub-session)"},
+				{reorderKeys, "Reorder up/down (auto-promote at edge)"},
+				{"Shift+→ / Shift+←", "Indent / outdent (in group)"},
 				{forkKeys, "Fork session (Claude only)"},
 				{copyKey, "Copy output to clipboard"},
 				{"C", "Copy preview info (Repo / Path / Branch)"},

skills/agent-deck/references/tui-reference.md

@@ -22,7 +22,8 @@ Complete reference for agent-deck Terminal UI features.
 | `n` | New session (inherits current group) |
 | `r` | Rename session or group |
 | `R` | Restart session (reloads MCPs) |
-| `K` / `J` | Move item up/down in order |
+| `K` / `J` | Move item up/down (auto-promotes a sub-session to top-level when at the parent's first/last child) |
+| `Shift+→` / `Shift+←` | Indent / outdent within current group (single-level nesting) |
 | `M` | Move session to different group |
 | `m` | Open MCP Manager (Claude/Gemini) |
 | `s` | Open Skills Manager |