feat(parser): remove step number prefixes from recipe extraction

- Update RECIPE_EXTRACTION_PROMPT to v2.1
- Remove instruction to number steps sequentially
- Update OUTPUT FORMAT and both few-shot examples
- Remove 'All steps numbered sequentially' from quality checklist
- Update fallback parser system prompt in parseRecipeWithStandardCompletion
- Frontend <ol> element already handles auto-numbering
- Tandoor integration unaffected (uses array index for step numbers)

Fixes double-numbering bug where steps appeared as '1. 1. Step text'
All 34 tests passing

Implementation follows execution plan in docs/plans/RemoveStepNumberPrefixes.md
Documented in docs/outcomes/RemoveStepNumberPrefixes.md

src/lib/server/parser.ts

@@ -146,7 +146,7 @@ async function parseRecipeWithStandardCompletion(text: string): Promise<Recipe>
   "servings": number or null,
   "description": "description in Italian or null",
   "ingredients": [{"item": "ingredient name", "amount": "quantity", "unit": "SI unit"}],
-  "steps": ["1. First step", "2. Second step", ...]
+  "steps": ["First step", "Second step", ...]
 }
 
 Convert all measurements to SI units (g, mL, °C).