fix: make tabName non-nullable to match runtime requirement

[sfrmattos]

Fixes #109

Problem

The tabName field in CreateRepeaterTab, CreateRepeaterTabHttp2, and SendToIntruder is declared as String? (nullable) in Kotlin. This causes kotlinx.serialization to exclude it from the JSON Schema's "required" array, so MCP clients omit the field — but the Burp Montoya API runtime requires it.

Result: Error: Field 'tabName' is required for type with serial name '...', but it was missing

Root cause

JsonSchema.kt line 54 checks !prop.returnType.isMarkedNullable — only non-nullable fields get added to the required array. String? is nullable, so the schema marks it optional. But the Montoya API's sendToRepeater(HttpRequest, String) has no null-handling overload.

Solution

Change String? → String in all 3 data classes. The Montoya API accepts any non-null String (including empty string), which is semantically equivalent to the original optional behavior.

Changes

• 3 lines in src/main/kotlin/net/portswigger/mcp/tools/Tools.kt
• Build verified: ./gradlew embedProxyJar → BUILD SUCCESSFUL
• JAR tested in Burp Pro — all 3 tools work correctly

Notes

This is intentionally minimal. An alternative would be String = "" with a conditional to call the 1-param overload when empty, but that adds unnecessary complexity.