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>

README.md

@@ -22,17 +22,20 @@ graph LR
 
 ## Controls
 
-- **Mouse-Left**: Click a module-button to launch it; click confirm/cancel in the quit-modal.
+- **Mouse-Left**: Select a module-row in the left list to show its detail; click Launch in the detail panel to launch it; carousel arrows; confirm/cancel in the modals.
-- **Enter**: Confirm quit when the modal is open.
+- **Mouse-Wheel**: Scroll the panel under the cursor — the module list (left) or the detail content (right). Detail content (description + dependencies) scrolls between the fixed hero strip and the fixed launch button.
-- **Escape**: Open the quit-modal from the chooser; cancel the modal when open.
+- **Enter**: Confirm quit when the quit-modal is open.
+- **Escape**: Open the quit-modal from the chooser; cancel the conflict/quit-modal when open.
 
 ## Demonstrates
 
 - `engine.module.list` discovery of installed modules from the modules-dir.
 - `engine.switch_module` runtime swap from the launcher to the selected module.
+- Master-detail UI: left list shows each module's **name** with a small genre-**tags** subline (from `manifest.launcher.md`); right panel shows hero carousel, rendered-markdown description, and per-dependency status.
+- Scrollable panels via `engine.render.begin_view`/`end_view` (scissor-clipped) driven by `engine.input.get_mouse_wheel`, with inline scrollbars.
 - Simple text + rect rendering via `engine.render` for the chooser UI.
 - Input-action binding through `lib-core.input` (`ui_click`, `ui_back`, `ui_confirm`).
-- Modal-state FSM (chooser <-> quit-modal) factored into a sibling `fsm.lua` loaded via `engine.module.dir_of`.
+- Modal-state FSM (chooser <-> quit/conflict-modal) factored into a sibling `fsm.lua` loaded via `engine.module.dir_of`.
 
 ## References
 

init.lua

@@ -199,7 +199,10 @@ function init(ctx)
         module_entries     = {},       -- filled below from engine.module.list
         news_entry         = { title = nil, body_path = "news.md" },
         selected_entry     = nil,
-        scroll_y           = 0,
+        scroll_y           = 0,          -- list-panel vertical scroll
+        detail_scroll_y    = 0,          -- detail-panel content scroll
+        detail_content_h   = 0,          -- set by detail.render each frame
+        detail_view_h      = 0,          -- scrollable viewport height, set by detail.render
         list_tint          = nil,      -- nil | "warn" | "error" — set in L.4
         list_panel_rect    = nil,      -- set below from window size
         detail_panel_rect  = nil,
@@ -263,6 +266,7 @@ function init(ctx)
         local meta, blocks = manifest_loader.load_for(entry.id)
         ctx_panels.manifest_cache[entry.id] = { meta = meta, blocks = blocks }
         entry.summary = meta.summary
+        entry.tags = meta.tags   -- L-fix: list-row subline (genre tags)
 
         -- L.4: also surface manifest.module::deps[] verbatim so the
         -- detail-panel can render per-dep status glyphs in load order
@@ -392,6 +396,16 @@ function update(ctx, dt)
     end
 
     if state == STATE_LIST then
+        -- Mouse-wheel scroll: route to whichever panel the cursor is over.
+        local wheel = engine.input.get_mouse_wheel()
+        if wheel ~= 0 then
+            if hit(ctx_panels.detail_panel_rect, mx, my) then
+                detail_panel.handle_scroll(ctx_panels, wheel)
+            elseif hit(ctx_panels.list_panel_rect, mx, my) then
+                list_panel.handle_scroll(ctx_panels, wheel)
+            end
+        end
+
         if input.was_action_pressed("ui_back") then
             state = fsm.next(state, "esc")
         elseif input.was_action_pressed("ui_click") then

panels/detail.lua

@@ -11,6 +11,11 @@ local FONT_TITLE    = 28
 local FONT_SUB      = 16
 local FONT_BODY     = 14
 local FONT_DEP      = 14
+local HERO_H        = 160   -- fixed hero strip (outside scroll region)
+local BOTTOM_RESERVE = 70   -- fixed launch-button strip (outside scroll region)
+local SCROLLBAR_W   = 6
+local COLOR_SCROLL_TRACK = 0x00000040
+local COLOR_SCROLL_THUMB = 0x707070FF
 
 local md  -- lazy-loaded markdown renderer
 
@@ -18,6 +23,38 @@ local function ensure_md(launcher_dir)
     if not md then md = dofile(launcher_dir .. "/markdown.lua") end
 end
 
+-- Camera that shifts content up by `scroll` px and clips to `view` (set up
+-- via engine.render.begin_view). Drawing inside uses absolute screen-space
+-- coords (zoom 1, target.x = view-center → x unchanged); only y scrolls.
+local function scroll_cam(view, scroll)
+    return {
+        target_x = view.x + view.w / 2,
+        target_y = view.y + view.h / 2 + scroll,
+        zoom     = 1,
+    }
+end
+
+-- Clamp the live scroll offset to [0, content - view] using last frame's
+-- measured content height. Returns the clamped value (also written back).
+local function clamp_scroll(ctx)
+    local max_scroll = math.max(0, (ctx.detail_content_h or 0) - (ctx.detail_view_h or 0))
+    ctx.detail_scroll_y = math.max(0, math.min(max_scroll, ctx.detail_scroll_y or 0))
+    return ctx.detail_scroll_y
+end
+
+-- Vertical scrollbar on the view's right edge (mirrors list.lua; kept inline
+-- per the Lib-Cut criterion — cognitive locality over de-duplication).
+local function draw_scrollbar(view, scroll, content_h)
+    if content_h <= view.h then return end
+    local track_x = view.x + view.w - SCROLLBAR_W - 2
+    engine.render.draw_rect(track_x, view.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 / max_scroll) or 0
+    local thumb_y = view.y + frac * (view.h - thumb_h)
+    engine.render.draw_rect(track_x, thumb_y, SCROLLBAR_W, thumb_h, COLOR_SCROLL_THUMB)
+end
+
 local function status_glyph(ctx, dep_status)
     if dep_status == "ok"    then return ctx.t("dep_glyph_ok"),      COLOR_OK   end
     if dep_status == "warn"  then return ctx.t("dep_glyph_warn"),    COLOR_WARN end
@@ -46,11 +83,18 @@ function M.render(ctx)
         return
     end
 
-    -- News: render news.md.
+    -- News: render news.md (scrollable, full panel — no hero/launch strip).
     if ctx.selected_entry == "news" then
         ensure_md(ctx.launcher_dir)
+        local view = { x = p.x, y = p.y, w = p.w, h = p.h }
+        local scroll = clamp_scroll(ctx)
+        engine.render.begin_view(view, scroll_cam(view, scroll))
         local body = ctx.news_body_blocks or {}
-        md.render(body, p.x + PADDING, p.y + PADDING, p.w - 2 * PADDING, nil)
+        local end_y = md.render(body, p.x + PADDING, p.y + PADDING, p.w - 2 * PADDING, nil)
+        engine.render.end_view()
+        ctx.detail_content_h = (end_y - view.y) + PADDING
+        ctx.detail_view_h = view.h
+        draw_scrollbar(view, scroll, ctx.detail_content_h)
         return
     end
 
@@ -58,18 +102,27 @@ function M.render(ctx)
     if not entry then return end
     local mc = ctx.manifest_cache[entry.id] or { meta = {}, blocks = {} }
 
-    -- Hero carousel (L.5). Renders bg + texture + arrows + dots.
+    -- Hero carousel (L.5) — fixed, above the scroll region. Renders bg +
-    -- Zero-teaser modules render the default_teaser_texture (L.10)
+    -- texture + arrows + dots. Zero-teaser modules render the
-    -- on top of the COLOR_FALLBACK_BG strip.
+    -- default_teaser_texture (L.10) on top of the COLOR_FALLBACK_BG strip.
-    local hero_h = 160
     local s = ctx.carousel_state[entry.id]
     if s and ctx.carousel_mod then
-        ctx.carousel_mod.render(s, p.x, p.y, p.w, hero_h, ctx.default_teaser_texture)
+        ctx.carousel_mod.render(s, p.x, p.y, p.w, HERO_H, ctx.default_teaser_texture)
     else
-        engine.render.draw_rect(p.x, p.y, p.w, hero_h, 0x404040FF)
+        engine.render.draw_rect(p.x, p.y, p.w, HERO_H, 0x404040FF)
     end
 
-    local cur_y = p.y + hero_h + PADDING
+    local r = entry.status.dep_check_result
+
+    -- Scroll region: everything between hero and the fixed launch strip.
+    local view = {
+        x = p.x, y = p.y + HERO_H,
+        w = p.w, h = p.h - HERO_H - BOTTOM_RESERVE,
+    }
+    local scroll = clamp_scroll(ctx)
+    engine.render.begin_view(view, scroll_cam(view, scroll))
+
+    local cur_y = view.y + PADDING
     -- Title row.
     local title = entry.summary or entry.name or entry.id
     engine.render.draw_text(title, p.x + PADDING, cur_y, FONT_TITLE, COLOR_TEXT)
@@ -89,7 +142,6 @@ function M.render(ctx)
     cur_y = cur_y + 12
 
     -- Dep list — load-order from manifest.module per L-Q6.
-    local r = entry.status.dep_check_result
     local dep_count = (r and r.deps and #r.deps) or 0
     engine.render.draw_text(
         string.format("%s (%d)", ctx.t("dependencies"), dep_count),
@@ -111,6 +163,13 @@ function M.render(ctx)
         end
     end
 
+    engine.render.end_view()
+
+    -- Record content/viewport extent for scroll-clamp (next frame) + bar.
+    ctx.detail_content_h = (cur_y - view.y) + PADDING
+    ctx.detail_view_h = view.h
+    draw_scrollbar(view, scroll, ctx.detail_content_h)
+
     -- Whole-list tint hint: bubble up to ctx.list_tint so panels/list.lua picks it up.
     if r and r.kind == "error" then ctx.list_tint = "error"
     elseif r and r.kind == "warn" then ctx.list_tint = "warn"
@@ -173,4 +232,10 @@ function M.handle_click(ctx, mx, my)
     return false
 end
 
+function M.handle_scroll(ctx, dy)
+    local max_scroll = math.max(0, (ctx.detail_content_h or 0) - (ctx.detail_view_h or 0))
+    ctx.detail_scroll_y = math.max(0,
+        math.min(max_scroll, (ctx.detail_scroll_y or 0) - dy * 24))
+end
+
 return M

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