perf(legacy-html): stop re-parsing shiki themes per code block

[araujogui]

Description

legacy-html passed theme objects to codeToHast. Shiki normalizes them into new objects, so its theme cache never hits and both themes are re-parsed for every code block (~3.8s CPU per build). The highlighter now loads the catppuccin themes and code is highlighted with them by name, as highlighter.mjs already does.

Validation

legacy-html on the Node.js API docs, 8 cores, 3 runs:

	wall	CPU	RSS
before	6.9–7.4s	33.4s	~1.45GB
after	4.8–5.0s	23.2s	~1.45GB

Output is byte-identical (diff -r over all 71 files). Tests, lint and format pass.

Check List

• I have read the Contributing Guidelines and made commit messages that follow the guideline.
• I have run node --run test and all tests passed.
• I have check code formatting with node --run format:check & node --run lint.
• I've covered new added functionality with unit tests if necessary.

[vercel]

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Project	Deployment	Actions	Updated
api-docs-tooling	Ready	Preview	Oct 18, 2026 1:36pm UTC

[Copilot]

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[codecov]

Codecov Report

❌ Patch coverage is 62.50000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.44%. Comparing base (560c042) to head (e2d83b9).

Files with missing lines	Patch %	Lines
...ages/node-legacy/src/legacy-html/plugins/shiki.mjs	62.50%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1169      +/-   ##
==========================================
- Coverage   93.44%   93.44%   -0.01%     
==========================================
  Files         278      278              
  Lines       27815    27820       +5     
  Branches     2789     2790       +1     
==========================================
+ Hits        25993    25997       +4     
- Misses       1800     1801       +1     
  Partials       22       22              

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[github-actions]

api-links Generator

Performance estimate _{(single CI run)}

• Generation time: 13.8% slower (650.00 ms → 740.00 ms)
• Peak memory: 0.8% lower (302.18 MB → 299.64 MB)

json Generator

Performance estimate _{(single CI run)}

• Generation time: 25.9% slower (7.48 s → 9.42 s)
• Peak memory: 2.2% higher (1.21 GB → 1.23 GB)

legacy-html Generator

Performance estimate _{(single CI run)}

• Generation time: 14.4% faster (14.67 s → 12.56 s)
• Peak memory: 5.7% lower (1.84 GB → 1.73 GB)

legacy-json Generator

Performance estimate _{(single CI run)}

• Generation time: 50.7% slower (5.82 s → 8.77 s)
• Peak memory: 8.8% lower (1.26 GB → 1.15 GB)

llms-txt Generator

Performance estimate _{(single CI run)}

• Generation time: 7.7% slower (7.57 s → 8.15 s)
• Peak memory: 1.2% lower (1.14 GB → 1.13 GB)

orama-db Generator

Output size: 1 file changed · net -1.00 B

File size details

File	Main	PR	Change
orama-db.json	29.15 MB	29.15 MB	-1.00 B (-0.0%)

Performance estimate _{(single CI run)}

• Generation time: 8.8% faster (5.65 s → 5.15 s)
• Peak memory: 3.5% higher (1.33 GB → 1.38 GB)

web Generator

Performance estimate _{(single CI run)}

• Generation time: 0.2% faster (24.88 s → 24.84 s)
• Peak memory: 2.8% lower (2.04 GB → 1.99 GB)

[ovflowd]

SGTM