Release v0.13.0

Summary

Minor release that bumps the bundled oxidize-pdf core from =2.16.3 to
=3.0.1 and surfaces the new upstream CID-keyed positioned-glyph-run write
path (issue #358) into the Python bridge. This lets callers draw a pre-shaped
glyph run — addressing glyphs directly by id, with per-glyph kerning and offset
— while keeping the result extractable as text.

No breaking change to the existing Python API: the upstream 3.0.0 breaking
changes touch only low-level font modules the bridge never used.

Added — CID-keyed positioned glyph runs (issue #358)

A pre-shaped glyph run (e.g. produced by a HarfBuzz-style shaper) can now be
embedded as an Identity-H Type0/CIDFontType2 font where the CID equals the
glyph id, drawn as a TJ array, and accompanied by a ToUnicode CMap so the
text stays searchable/extractable. The embedded font is subset to the used
glyph ids.

New surface:

• CidMapping(cid_to_gid=..., cid_to_unicode=..., cid_to_unicode_str=..., max_cid=...) — keyword dicts populate the underlying maps; max_cid is
  auto-derived as the largest CID across every map when omitted.
  cid_to_unicode_str lets a single CID (e.g. an fi ligature glyph)
  decompose to several characters in the ToUnicode CMap.
• CidShowElement(cid, adjust) with .with_x_offset(offset) and cid /
  adjust / x_offset accessors. adjust is the post-glyph advance kern
  (TJ convention); x_offset displaces a glyph without consuming advance
  (GPOS mark attachment / diacritics).
• Document.add_cid_keyed_font(name, data, mapping) — registers a CID-keyed
  font on a path kept separate from the Unicode-keyed embedding path. Only
  TrueType/SFNT (CIDFontType2) fonts are supported.
• Page.set_custom_font(name, size) — selects the active custom font for
  subsequent drawing (required before show_cid_array).
• Page.show_cid_array(elements, x, y) — writes the positioned glyph run.

Changed — upstream bump to oxidize-pdf 3.0.1

• 3.0.0 introduces the CID glyph-run API above and a subset-by-used-GIDs
  embedding path for it.
• 3.0.1 fixes font loss when a merged page's /Resources references /Font
  indirectly (/Font 1 0 R) rather than inline.

The two upstream 3.0.0 breaking changes (removal of the non-functional
truetype_subsetting glyph subsetter; CidMapping becoming #[non_exhaustive])
do not affect the bridge — neither symbol was used in bridge source.

Fixed — MCP convert_pdf parameter description

The max_tokens parameter description claimed it applied to format='rag', but
the rag path calls rag_chunks() with a fixed internal budget and ignores it.
The description now states max_tokens applies to format='chunks' only. A
characterization test pins that rag output is independent of max_tokens.

Tests

• New tests/test_issue_358_cid_glyph_run.py: builds a CID-keyed font with
  CIDs distinct from their GIDs, draws a positioned run (including an fi
  ligature CID), and verifies the end-to-end contract on real bytes —
  Type0/CIDFontType2/Identity-H structure, the CID codes in the TJ
  content stream, and a text-extraction round-trip yielding fix via the
  ToUnicode CMap.
• New characterization test in tests/mcp_tests/test_tool_convert_pdf.py for
  the max_tokens/rag contract.
• Full suite green; mypy clean; cargo check/cargo fmt clean.

Compatibility

• Python 3.10+, cp310-abi3 wheels (unchanged).

Breaking Changes

None to the Python API.