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.

tools/rom_data.py

@@ -11,8 +11,9 @@ from dataclasses import dataclass
 CANONICAL_RED_SHA1 = "ea9bcae617fdf159b045185467ae58b2e4a48b9a"
 CANONICAL_BLUE_SHA1 = "d7037c83e1ae5b39bde3c30787637ba1d4c48ce2"
 CANONICAL_YELLOW_SHA1 = "cc7d03262ebfaf2f06772c1a480c7d9d5f4a38e1"
-# Gold is Gen 2: a 2 MiB cart, twice the size of the Gen 1 ROMs above.
+# Gold and Silver are Gen 2: 2 MiB carts, twice the size of the Gen 1 ROMs above.
 CANONICAL_GOLD_SHA1 = "d8b8a3600a465308c9953dfa04f0081c05bdcb94"
+CANONICAL_SILVER_SHA1 = "49b163f7e57702bc939d642a18f591de55d92dae"
 ROM_BANK_SIZE = 0x4000