feat: redesign installer on MTK toolkit with component selection

Rewrite the Installer app on the Montauk Toolkit (Canvas + gui/mtk
widgets, theme, hover states, scrollbar) replacing the hand-rolled px_*
renderer and bespoke TrueType usage.

Add a new "Software" step: an expandable checkbox tree for optional
components (Montauk SDK with gcc/g++, binutils, tcc, lua sub-items;
Games; Office; Internet apps; Printing; experimental httpd and SDR).
Unchecked components' paths are excluded from the install copy, with a
longest-path ownership rule so e.g. sdk/tcc installs even when the rest
of the SDK is deselected. The update flow refreshes only the components
the target already has.

Add tri-state checkbox and disclosure-arrow widgets to the MTK toolkit
(anti-aliased, supersampled).

Merge tcc and lua into 0:/sdk (0:/sdk/tcc, 0:/sdk/lua) and drop 0:/lib:
update tcc config.h, lua luaconf.h, both Makefiles, the devkit clean
scope, man pages and montaukos.org notices.

Make printing optional: init skips printd when 0:/os/printd.elf is
absent.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

programs/man/intro.1

@@ -52,13 +52,14 @@
         0:/icons/       Shared icons
         0:/man/         Manual pages
         0:/www/         Web server content
-        0:/lib/         Lua and TinyCC toolchain payloads
+        0:/sdk/         Montauk SDK (native gcc/binutils, TinyCC,
+                        Lua, headers and libraries), when installed
         0:/boot/        Kernel, bootloader, ramdisk image
 
     There is no 0:/games/, 0:/common/, 0:/home/, or 0:/etc/ --
     these were used by earlier single-user releases and no longer
-    exist. Games and other GUI programs (including doom) ship as
-    bundles under 0:/apps/.
+    exist. 0:/lib/ was merged into 0:/sdk/. Games and other GUI
+    programs (including doom) ship as bundles under 0:/apps/.
 
 .SH SHELL
     The interactive shell is the primary way to interact with