fix(chart): render chart JSON from json/untagged fences#25
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…chart Small on-device models (Gemma E2B, the default) reliably emit valid chart JSON but tag the fence ```json or leave it untagged — never ```chart — even when explicitly instructed. So the chart feature from #23 never rendered in practice; the block fell back to a code block. Now we also attempt ChartParser.parse on json/untagged fences and render a chart when it succeeds. ChartParser only returns non-null for JSON with a recognized chart type (donut/bar/progress/line + synonyms) AND valid data, so ordinary JSON code samples still render as code. The explicit ```chart path is unchanged. Verified on-device (Realme CPH2723, release): historical Gemma answers that emitted untagged chart JSON now re-render as a donut + bar charts. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Why
#23 added inline charts: the model is meant to emit a
chart-tagged fenced JSON block, which `MarkdownText` detects via `lang == "chart"`. But on-device verification showed the default **Gemma 4 E2B reliably emits valid chart JSON taggedjson (or untagged) — never ```chart**, even when forcefully instructed. So charts never rendered in practice; the block fell back to a code block.Fix
MarkdownTextnow also attemptsChartParser.parseonjson/untagged fences and renders a chart when it succeeds. This is conservative:ChartParseronly returns non-null for JSON with a recognized charttype(donut/bar/progress/line + synonyms) and valid data, so ordinary JSON code samples still render as code. The explicit ```chart path is unchanged.Verified on-device
Realme CPH2723, release build: historical Gemma answers that had emitted untagged chart JSON now re-render as a donut chart (Monthly Budget) and bar charts (Quarterly Sales, Users) — proper on-brand Canvas charts, not code blocks.
🤖 Generated with Claude Code