fix: validate numeric request parameters strictly

[winklemad]

Summary

• Validate numeric query, path, and header parameters as complete signed decimal values, including decimal fractions and exponent notation.
• Reject partially numeric values, empty or whitespace-only values, and hexadecimal, binary, or octal inputs instead of silently coercing them.
• Add endpoint-level regressions covering accepted and rejected parameter values across query, path, and header inputs.

Changes

• Replace prefix-based parsing with an anchored decimal-number check before numeric conversion.
• Add a patch changeset for the stricter request-parameter behavior.

Tests

• npm test -- parameters.test.ts
• npm test
• npm run build
• npm run lint
• npx changeset status

Related context

Related context: #139 and #151

[pkg-pr-new]

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npm i https://pkg.pr.new/cloudflare/chanfana@346

commit: 750c6b9