Lack of italic glyphs for Greek and Cyrillic scripts

It says:
> ### Upright Versus Italic
> _Source Han Mono_ includes 551 Latin, Greek, and Cyrillic glyphs that were derived from _Source Code Pro_. The only characters with proportional-width glyphs in _Source Han Sans_ that are not included are for U+FB00, U+FB03, U+FB04, and U+1F16A through U+1F16C.
> Also included are 410 _italic_ glyphs that were derived from _Source Code Pro_. In addition to the lack of _italic_ glyphs for the Greek and Cyrillic scripts, except for U+03C0 _π_ (Greek), the glyphs for the following 26 characters are provided only in upright form for space-efficiency, and because the upright and _italic_ glyphs are identical in _Source Code Pro_: U+0020 (_space_), U+002B +, U+003C <, U+003D =, U+003E >, U+007C |, U+007E ~, U+00A6 ¦, U+00AC ¬, U+00B1 ±, U+00D7 ×, U+00F7 ÷, U+2016 ‖, U+212E ℮, U+2190 ←, U+2191 ↑, U+2192 →, U+2193 ↓, U+2194 ↔, U+2195 ↕, U+2196 ↖, U+2197 ↗, U+2198 ↘, U+2199 ↙, U+2212 −, and U+2713 ✓.
> The _italic_ glyphs are accessible via two mechanisms:
• By selecting an _italic_-style font, either by explicitly selecting the font or via an “Italic” style button that is provided by some apps.
• By enabling the 'ital' (_Italics_) GSUB feature, which is included in the non-_italic_ fonts.

The issue only quotes the “Upright Versus Italic” section and names no repository files or tests. Start by verifying the documented Greek and Cyrillic italic coverage in Source Han Mono against the stated behavior; define the missing glyph set and an acceptance check before estimating implementation.

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