add simulator mode to desktop designer for testing apps

- Add --simulator flag to launch home screen showing discovered apps
- Create app discovery system to scan test-apps/ directory
- Build simulator home screen with dark phone-like UI
- Add Lua API: simulator.launchApp, simulator.goHome, simulator.getApps
- ESC key returns to home when inside an app
- Apps displayed with icons in grid layout

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

designer/assets/simulator/simulator.lua

@@ -0,0 +1,158 @@
+-- Simulator Home Screen Logic
+
+local apps = {}
+
+-- Helper to get document (may not be available immediately)
+local function getDoc()
+    if document then
+        return document
+    end
+    if rmlui and rmlui.contexts and rmlui.contexts.main then
+        local ctx = rmlui.contexts.main
+        if ctx.documents then
+            for i, doc in ipairs(ctx.documents) do
+                if doc then
+                    return doc
+                end
+            end
+        end
+    end
+    return nil
+end
+
+-- Populate the app grid with discovered apps
+function populateAppGrid()
+    local doc = getDoc()
+    if not doc then
+        print("[Simulator] Document not available for populateAppGrid")
+        return
+    end
+
+    local grid = doc:GetElementById("app-grid")
+    if not grid then
+        print("[Simulator] app-grid element not found")
+        return
+    end
+
+    -- Clear existing content
+    grid.inner_rml = ""
+
+    if #apps == 0 then
+        grid.inner_rml = [[
+            <div class="no-apps">
+                <p>No apps found</p>
+                <p class="hint">Place apps in test-apps/ folder</p>
+            </div>
+        ]]
+        return
+    end
+
+    -- Build app icons
+    local html = ""
+    for i, app in ipairs(apps) do
+        local icon_html
+        if app.icon and app.icon ~= "" then
+            icon_html = string.format('<img src="%s"/>', app.icon)
+        else
+            icon_html = '<span class="app-icon-placeholder">&#x25A0;</span>'
+        end
+
+        html = html .. string.format([[
+            <div class="app-icon" onclick="launchApp('%s')">
+                <div class="app-icon-image">%s</div>
+                <span class="app-icon-label">%s</span>
+            </div>
+        ]], app.id, icon_html, app.name)
+    end
+
+    grid.inner_rml = html
+    print("[Simulator] Populated " .. #apps .. " apps")
+end
+
+-- Get apps from C++ and populate the grid
+function refreshApps()
+    if simulator and simulator.getApps then
+        apps = simulator.getApps()
+        print("[Simulator] Got " .. #apps .. " apps from C++")
+        populateAppGrid()
+    else
+        print("[Simulator] simulator.getApps not available")
+    end
+end
+
+-- Called from C++ after apps are discovered (backup method)
+function setApps(app_list)
+    apps = app_list
+    populateAppGrid()
+end
+
+-- Launch an app by ID
+function launchApp(app_id)
+    print("[Simulator] Launching app: " .. app_id)
+
+    -- Find the app
+    for _, app in ipairs(apps) do
+        if app.id == app_id then
+            -- Call C++ function to launch the app
+            if simulator and simulator.launchApp then
+                simulator.launchApp(app.entry, app.path, app.id)
+            else
+                print("[Simulator] Error: simulator.launchApp not available")
+            end
+            return
+        end
+    end
+
+    print("[Simulator] App not found: " .. app_id)
+end
+
+-- Update the time display
+function updateTime()
+    local doc = getDoc()
+    if not doc then return end
+
+    local timeEl = doc:GetElementById("status-time")
+    if timeEl then
+        -- Use os.date if available, otherwise show static time
+        local time_str = "12:00"
+        if os and os.date then
+            time_str = os.date("%H:%M")
+        end
+        timeEl.inner_rml = time_str
+    end
+end
+
+-- Initialize
+print("[Simulator] Home screen loaded")
+
+-- Try immediate initialization first
+local doc = getDoc()
+if doc then
+    print("[Simulator] Document available immediately")
+    refreshApps()
+    updateTime()
+elseif setInterval then
+    print("[Simulator] Document not ready, setting up timer")
+    -- Use a one-time timer to refresh apps after document is ready
+    local initTimerId = nil
+    local attempts = 0
+    initTimerId = setInterval(function()
+        attempts = attempts + 1
+        local d = getDoc()
+        if d then
+            print("[Simulator] Document ready after " .. attempts .. " attempts")
+            clearInterval(initTimerId)
+            refreshApps()
+            updateTime()
+        elseif attempts > 50 then
+            -- Give up after 5 seconds
+            print("[Simulator] Gave up waiting for document")
+            clearInterval(initTimerId)
+        end
+    end, 100)
+
+    -- Update time every minute
+    setInterval(updateTime, 60000)
+else
+    print("[Simulator] No setInterval and no document - cannot init")
+end