Converter mappings: data-quality fixes (no-op transforms, NaN outputs, sparse path, phantom angular-material)

[ch-bas]

Where: conversion mappings (lib/converter/mappings.ts)

Findings from a data audit of all 44 paths:

• 11 no-op transforms return '' for both branches, so the prop is emitted as an empty string instead of being dropped or mapped. Affected (line numbers as of current main): MUI→AntD Button color→danger (222), AntD→MUI Input status→error (1046), AntD→Chakra Input status→isInvalid (1185), AntD→Quasar Input status→error (1322), EUI→AntD Button color→danger (2173), MUI→EUI Button variant→fill (2498), Chakra→EUI Button variant→fill (2658), AntD→EUI Button type→fill (2818) and Input status→isInvalid (2836), Bootstrap→EUI Button variant→fill (2960), Mantine→EUI Button variant→fill (3563).
• 2 transforms can emit "NaN" on non-numeric input: Bootstrap→Quasar ProgressBar now (1815), MUI→Mantine Card elevation (4518). Add numeric guards.
• MANTINE_TO_TAILWIND has only 17 components (5882) vs. 42–57 in every other path — users hitting this path will see most components pass through.
• angular-material is declared in the FrameworkTarget type but has zero mappings — remove it from the type or implement the paths (same phantom-Angular pattern as compat: missing Angular, unreliable matching, dead code, incomplete component index #6 in the CLI).

[ch-bas]

Now that #15 makes unconverted components visible instead of silently passing them through, two concrete mapping gaps surface in the bundled examples and should be folded into this data-quality pass:

• Typography has no mapping in MUI→Quasar — the mui-button-group and mui-card examples now report it skipped.
• Bootstrap's compound Card.Body / Card.Title / Card.Text are unmapped in every Bootstrap→ path* (only the Form.* dotted keys exist).

These are true positives (genuinely missing mappings), not regressions from the #15 fix.