fix(generate-markdown): display output type for transform schemas

[CatchMe2]

• Use outputSchema.type (with inputSchema.type as fallback) when rendering the Type: field in generated markdown docs, so transform-based schemas like z.stringbool() display their output type (boolean) rather than their input type (string)
• Add z.stringbool().default(false) test case to the markdown generation test
• Fix z.number() test schemas to use stringToNumberSchema / z.coerce.number() — env vars are always string | undefined, bare z.number() schemas were misleading