`evidence validate` exits 0 on critical markdown parse errors

[hpcnt-jerry-l]

Summary

evidence validate reports valid: true and exits 0 when a page contains a critical Markdoc parse error — e.g. an undefined tag. The same page renders a page-level error box in serve, so the command gives a false all-clear for pages the app renders as broken.

Environment

• Evidence CLI v0.10.1
• No warehouse connection needed (syntax-only mode)

Steps to reproduce

{% unknown_tag /%}

evidence validate --json

Actual

{"valid":true,"fileCount":1,"errorCount":0,"warningCount":0}

exit code 0. The per-file output still contains the error — it is just not counted:

{"line":1,"endLine":1,"severity":"critical","message":"Undefined tag: 'unknown_tag'","id":"tag-undefined"}

Expected

Nonzero exit for critical parse errors. The CLI's human report already prints critical entries in red as errors, and serve renders them as a page-level error box.

Root cause

cli/src/routes/api/validate/+server.ts maps every validationErrors entry to the output (severity: err.error.level), but the aggregation only counts 'error':

totalErrors += errors.filter((e) => e.severity === 'error').length;
totalWarnings += errors.filter((e) => e.severity === 'warning').length;

Markdoc classifies structural errors (tag-undefined, missing-opening, tag-placement-invalid, ...) as level: 'critical', which falls into neither bucket:
errorCount: 0, warningCount: 0, valid: true.

Suggested fix

totalErrors += errors.filter((e) => e.severity === 'error' || e.severity === 'critical').length;

Impact

Medium. Anyone relying on evidence validate's exit code gets a false green on pages that serve renders with an error box. A "treat warnings as errors" style option would not help — critical entries are counted as neither errors nor warnings.

[hpcnt-jerry-l]

Thanks for the quick turnaround on this, @tojacob03 @hughess !