fix(chart): improve error handling and color variety

- Add quotaExceeded flag to response for better error UX
- Show dedicated quota exceeded state with upgrade button
- Improve AI prompt to better detect data patterns
- Add chart type-specific colors (blue, indigo, emerald, violet, etc.)
- Replace generic primary/10 colors with varied accent colors

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

memento-note/app/api/ai/suggest-charts/route.ts

@@ -90,11 +90,23 @@ export async function POST(req: Request) {
       model: provider(model),
       system: `You are a data visualization assistant. Analyze the provided text and suggest appropriate chart types.
 
-CRITICAL: Extract ONLY numerical data present in the text. Do NOT invent values.
+DATA EXTRACTION RULES:
+- Extract ANY numerical data present in the text
+- Look for patterns like: "X: 123", "X = 123", "X is 123", "X (123)", "123X", "X $123", "123%"
+- Accept partial data (e.g., if only 2 values exist, that's still valid for a simple chart)
 - If fewer than 2 data points exist, return hasData=false with empty suggestions
 - Each suggestion must use the SAME extracted data (only chart type differs)
 - Return exactly 3 suggestions when data exists
-- Provide clear rationale for each chart type choice
+
+CHART TYPE SELECTION:
+- bar: Comparing values across categories (default choice)
+- horizontal-bar: Categories with long labels
+- line: Time series or sequential data
+- area: Time series where magnitude matters
+- pie: Parts of a whole (percentages or proportions)
+- radar: Comparing multiple dimensions
+- funnel: Stages or conversion steps
+- gauge: Single value vs target
 
 Response format (JSON):
 {