fix(cpp-boost-beast): validate request components

[bold84]

Summary

• validate method tokens, origin-form request targets, percent escapes, and caller-provided headers before serializing requests
• reject transport-owned framing headers and unsafe host/port input while preserving service-name ports and extension methods
• regenerate the Petstore client and add template plus runtime regression coverage

Verification

• ./mvnw -pl modules/openapi-generator -am -Dtest=CppBoostBeastClientCodegenTest -Dsurefire.failIfNoSpecifiedTests=false -Djacoco.skip=true test
• ./mvnw -pl modules/openapi-generator-cli -am package -DskipTests -Dmaven.javadoc.skip=true
• bin/generate-samples.sh bin/configs/cpp-boost-beast-client-petstore.yaml
• CMake build of api_tests
• HttpClientBehaviorTest/* (9 tests)

---

Summary by cubic

Hardens the cpp-boost-beast HTTP client by validating method, target, headers, host, and port to prevent unsafe input and reserved header misuse. Preserves custom/extension methods and regenerates the Petstore client with tests.

• Bug Fixes
  • Validate method tokens, origin-form targets (with percent escapes), and header names/values; reject control characters.
  • Block caller-supplied transport/framing headers (Host, Content-Length, Transfer-Encoding, Connection, Proxy-Connection, Keep-Alive, TE, Trailer, Expect, Proxy-Authorization).
  • Validate host and port; allow service-name ports and custom methods.
  • Use request.method_string(verb) and explicit target/body; keep correct IPv4/IPv6 Host formatting.
  • Add regression tests and regenerate the Petstore client.

^{Written for commit 906500c. Summary will update on new commits.}

[cubic-dev-ai]

No issues found across 4 files

_{Re-trigger cubic}