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.

docs/required-to-function.md

@@ -1,7 +1,8 @@
 # What This Port Requires
 
 The packaged desktop app requires one user-supplied input on first boot: a
-canonical 1 MiB US Pokemon Red, Blue, or Yellow ROM.
+canonical 1 MiB US Pokemon Red, Blue, or Yellow ROM, or a canonical 2 MiB US
+Pokemon Gold or Silver ROM.
 
 The importer verifies the SHA-1 for the game (see `src/core/GameVersion.lua`
 for specific hashes). Other revisions and Virtual Console releases are rejected
@@ -15,7 +16,8 @@ Python and Pillow are not required by the packaged app.
 
 Assembly removes high-level names and some relationships that the Lua port
 needs. The version-specific files `tools/rom_manifest.json`,
-`tools/rom_manifest_blue.json`, and `tools/rom_manifest_yellow.json` therefore
+`tools/rom_manifest_blue.json`, `tools/rom_manifest_yellow.json`,
+`tools/rom_manifest_gold.json`, and `tools/rom_manifest_silver.json` therefore
 contain:
 
 - the ROM symbol addresses actually read by the extractor