feat(launcher): trim list rows to name+tags, scrollable detail panel

List rows showed the long `summary` (name+id+description fallback chain)
and overflowed. Now each row shows the module name with a small genre-
tags subline sourced from manifest.launcher.md (meta.tags, threaded onto
the entry in init). The list also scrolls properly now (wheel dispatch +
upper clamp) — it was wired but dead without a wheel binding.

Detail panel: description + dependency list ran off the bottom of the
window. The mid-section (title/description/deps) now scrolls inside a
begin_view/end_view scissor region between the fixed hero strip and the
fixed launch button; news view scrolls too. Both panels get an inline
scrollbar. Detail scroll resets on module switch.

Depends on engine.input.get_mouse_wheel (sporel-engine). README controls/
demonstrates synced.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

panels/list.lua

@@ -9,7 +9,34 @@ local COLOR_ROW_HOVER   = 0x404040FF
 local COLOR_ROW_ACTIVE  = 0x505080FF
 local COLOR_TEXT        = 0xE0E0E0FF
 local COLOR_DIM         = 0xA0A0A0FF
+local COLOR_TAGS        = 0x8090A0FF
 local FONT              = 18
+local FONT_TAGS         = 13
+local SCROLLBAR_W       = 6
+local COLOR_SCROLL_TRACK = 0x00000040
+local COLOR_SCROLL_THUMB = 0x707070FF
+
+-- Total scrollable content height for the current entry set (news row +
+-- all module rows). Used for scroll-clamp + scrollbar sizing.
+local function content_height(ctx)
+    local rows = #ctx.module_entries + (ctx.news_entry and 1 or 0)
+    if rows == 0 then return 0 end
+    return rows * (ROW_HEIGHT + ROW_GAP) - ROW_GAP + 2 * PADDING
+end
+
+-- Draw a vertical scrollbar inset on the panel's right edge when content
+-- overflows the viewport. Mirrors detail.lua's scrollbar (kept inline in
+-- both panels for cognitive locality — see Lib-Cut criterion).
+local function draw_scrollbar(p, scroll_y, content_h, view_h)
+    if content_h <= view_h then return end
+    local track_x = p.x + p.w - SCROLLBAR_W - 2
+    engine.render.draw_rect(track_x, p.y, SCROLLBAR_W, view_h, COLOR_SCROLL_TRACK)
+    local thumb_h = math.max(24, view_h * view_h / content_h)
+    local max_scroll = content_h - view_h
+    local frac = (max_scroll > 0) and (scroll_y / max_scroll) or 0
+    local thumb_y = p.y + frac * (view_h - thumb_h)
+    engine.render.draw_rect(track_x, thumb_y, SCROLLBAR_W, thumb_h, COLOR_SCROLL_THUMB)
+end
 
 -- Returns the rect rect-table {x,y,w,h} of the row for entry index i.
 function M.row_rect(ctx, i)
@@ -22,9 +49,16 @@ function M.row_rect(ctx, i)
     }
 end
 
--- Pick the display label per spec L-Q8: summary || name || id.
+-- Row title: name only (the long `summary` moved to the detail panel).
 local function label_for(entry)
-    return entry.summary or entry.name or entry.id
+    return entry.name or entry.id
+end
+
+-- Compact genre-tag subline ("Mittelalter · Hightech"), or nil if the
+-- module's manifest.launcher.md carries no tags.
+local function tags_line(entry)
+    if not entry.tags or #entry.tags == 0 then return nil end
+    return table.concat(entry.tags, " · ")
 end
 
 function M.render(ctx)
@@ -55,21 +89,36 @@ function M.render(ctx)
             local col = COLOR_ROW
             if ctx.selected_entry == entry.id then col = COLOR_ROW_ACTIVE end
             engine.render.draw_rect(rect.x, rect.y, rect.w, rect.h, col)
+            -- Module name on top, genre tags small below.
             engine.render.draw_text(label_for(entry),
-                rect.x + PADDING, rect.y + PADDING, FONT, COLOR_TEXT)
+                rect.x + PADDING, rect.y + 8, FONT, COLOR_TEXT)
+            local tags = tags_line(entry)
+            if tags then
+                engine.render.draw_text(tags,
+                    rect.x + PADDING, rect.y + 8 + FONT + 6, FONT_TAGS, COLOR_TAGS)
+            end
         end
         entry.rect = rect
     end
+
+    draw_scrollbar(p, ctx.scroll_y, content_height(ctx), p.h)
+end
+
+-- Selecting a different entry resets the detail panel's scroll so the new
+-- module's content starts from the top.
+local function select(ctx, id)
+    if ctx.selected_entry ~= id then ctx.detail_scroll_y = 0 end
+    ctx.selected_entry = id
 end
 
 function M.handle_click(ctx, mx, my)
     if ctx.news_entry and engine.spatial.aabb_contains_point(ctx.news_entry.rect, mx, my) then
-        ctx.selected_entry = "news"
+        select(ctx, "news")
         return true
     end
     for _, entry in ipairs(ctx.module_entries) do
         if entry.rect and engine.spatial.aabb_contains_point(entry.rect, mx, my) then
-            ctx.selected_entry = entry.id
+            select(ctx, entry.id)
             return true
         end
     end
@@ -77,7 +126,9 @@ function M.handle_click(ctx, mx, my)
 end
 
 function M.handle_scroll(ctx, dy)
-    ctx.scroll_y = math.max(0, ctx.scroll_y - dy * 24)
+    local p = ctx.list_panel_rect
+    local max_scroll = math.max(0, content_height(ctx) - p.h)
+    ctx.scroll_y = math.max(0, math.min(max_scroll, ctx.scroll_y - dy * 24))
 end
 
 return M