Pokemon Silver as a full launcher version, plus launcher mods-list and title-tempo fixes

Silver: derived import manifest (tools/make_silver_manifest.py re-resolves
the Gold manifest's symbols from pokesilver.sym), silver GameVersion row,
generation-keyed extractor routing, required-files override, edition save
stamping (a Silver playthrough no longer writes into the Gold save),
checkver-driven edition data, SILVER/KAMON/OSCAR/MAX presets, GOLD rival
default, edition credits banner, Lugia title screen (OAM layouts, bob,
trail, palettes as title.lua data keys with Gold defaults so old caches
need no re-import), packaging for every build target, docs, and tests.

Launcher: the installed-mods list is one continuous scroll (rows culled to
the viewport) instead of a pager with an inner scroll viewport; the pad
cursor's edge-scroll no longer runs it to the bottom. The game dropdown
shows just the initial and caret. Find-tab behavior unchanged.

Title tempo: a sprite-anim frame shows duration+1 ticks
(engine/sprite_anims/core.asm GetSpriteAnimFrame), which locks both
editions' 64-tick wing beat to the 64-tick sine bob; the title screens no
longer run fast and out of phase.

tests/engine/uwp_baseroms_test.lua

@@ -81,7 +81,8 @@ local function importer(ready)
   }, RomImporter)
 end
 
-local allReady = importer({ red = true, blue = true, yellow = true, gold = true })
+local allReady = importer({ red = true, blue = true, yellow = true, gold = true,
+  silver = true })
 allReady:_queueBaseRomScan()
 eq(allReady.baseRomScan.state, "done", "ready launcher skips discovery")
 eq(listings, 0, "ready launcher does not enumerate baseroms")
@@ -123,7 +124,8 @@ eq(picks, 0, "missing detected ROM does not open the picker unexpectedly")
 missing:choose("red")
 eq(picks, 1, "the next import attempt falls back to the native picker")
 
-local rescanned = importer({ red = true, blue = true, yellow = true, gold = true })
+local rescanned = importer({ red = true, blue = true, yellow = true, gold = true,
+  silver = true })
 rescanned.baseRoms.red = { path = "baseroms/z-red.gb", name = "z-red.gb" }
 rescanned:reimport("red")
 check(rescanned.baseRoms.red == nil, "re-import clears the detected ROM")