[devin-ai-integration]

Summary

PDF export ignored math — $…$/$$…$$ printed as raw LaTeX with the $ stripped (delimiters are concealed by md::Analysis, so the spans vanished but the source leaked through as plain text). This PR renders math in the PDF with the same Unicode approximation the editor already uses.

How: src/math.rs gains a pub(crate) pieces() API — the same walker as subs(), refactored into a shared scan(src, failed) that additionally reports every construct it could not read (unknown commands, scripts with no glyphs, malformed \frac args) as Piece { range, text: None }. No conversion tables were duplicated; subs()/approx() are unchanged for the editor.

src/pdf.rs now handles Analysis.maths in special()/special_start() — the same arm that already covers images, wiki-links and footnotes:

• Inline $…$ → converted runs in an italic DejaVu face (math_style()).
• $$…$$ with block: true → centered Paragraph on its own line (flow.element(…).aligned(Center)).
• Piece { text: None } → the LaTeX source in mono (mono_style()) so \foo{n} or e^{i\pi} reads as source, not broken glyphs.
• Money guards are untouched — R$ 10 e $ 20 still parses as plain prose (math_spans behavior unchanged).

Font coverage: every bundled Noto face misses ~half of the 416 characters math.rs can emit (all arrows, ∑ ≤ ∞ ∫, phonetic super/subscripts, double-struck). The exporter now embeds a pyftsubset-built DejaVu Sans + DejaVu Sans-Oblique subset covering ASCII, Latin-1/Ext-A, Greek, Cyrillic, General Punctuation and the whole math charset — +286 KB in the binary (DejaVuSans-math-subset.ttf 149 KB + DejaVuSans-Oblique-math-subset.ttf 137 KB), same ~286 KB per exported PDF since genpdf embeds the fonts it uses. License included (assets/fonts/DejaVu-LICENSE.txt, Bitstream Vera). Four emittable chars DejaVu lacks (⌢ ⌣ ⨆ ⨿) are listed in MATH_TOFU — a run containing them falls back to LaTeX source instead of showing .notdef boxes.

Tests: math_converts_to_unicode (inline + display through the real Emitter/inline path), unconvertible_math_shows_its_source, money_amounts_stay_literal, math_glyphs_reach_the_pdf (asserts the converted codepoints appear in the embedded font's ToUnicode CMap — i.e. real glyphs were drawn, not tofu).

Verified in the app: exported a note via the real "Export as PDF…" flow and opened the PDF in Preview — all glyphs render (α² ≤ ∞, xᵢ → ∑ᵢ, ∫₀¹, √(c), →), no tofu. PDFKit text extraction confirms:

Inline α² ≤ ∞ and xᵢ → ∑ᵢ xᵢ done.
∫₀¹ f(x) = (a)/(b) + √(c) + lim_n → ∞ n
Fallback keeps source: e^iπ and \foo{n}.
Money: R$ 10 e $ 20 literal.

The PDF (Preview):

Same note in the editor for comparison:

Link to Devin session: https://app.devin.ai/sessions/a075cd854db947cdb802a60f4e413e85
Open in Devin Desktop: https://app.devin.ai/desktop/session/a075cd854db947cdb802a60f4e413e85?variant=devin
Requested by: @horizzon3507

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring