Treat emoji + VS16 sequences as double-width - #5262
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Some emojis, such as U+2764 ❤ (HEAVY BLACK HEART), U+1F5E1 🗡 (DAGGER KNIFE) and U+1F5FA 🗺 (WORLD MAP), are narrow by default (Emoji_Presentation=No) and only take on their double-width emoji form when immediately followed by U+FE0F VARIATION SELECTOR-16. WcWidth previously ignored this context and always reported them as width 1, so TerminalRenderer's font-width-mismatch correction would scale the naturally wide glyph down to fit a single narrow cell, producing the reported squished rendering. WcWidth gains a table of the 219 code points with Emoji=Yes but Emoji_Presentation=No (derived from Unicode 15's emoji-data.txt) and a lookahead-aware width(chars, index[, limit]) that reports width 2 for one of these code points immediately followed by VARIATION_SELECTOR_16. TerminalRow#setChar widens the column for such a sequence instead of treating the selector as an ordinary zero-width combining mark, and TerminalEmulator advances the cursor to match. TerminalRenderer measures the selector along with its base character so the glyph's natural width is detected and no longer scaled down. Fixes termux#5251
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Summary
Emoji=Yes/Emoji_Presentation=Nobases when immediately followed by U+FE0F.Fixes #5251
Test plan
./gradlew :terminal-emulator:test(139 tests, including new VS16 cases)terminal-viewcompile