feat(go-avahi): implement stateful daemon-aware fuzzing and pure Go DNS decoding harnesses

[rishavtarway]

This Pull Request finalizes the fuzzing setup for the go-avahi project within the OpenPrinting/fuzzing repository. The changes expand the existing fuzzing suite to cover both stateful interactions with the avahi-daemon and critical pure Go logic paths, significantly increasing the library's overall test coverage against malformed or adversarial inputs.

Technical Achievements:

• Stateful Lifecycle Fuzzing: Introduced harnesses for EntryGroup and ServiceBrowser lifecycles. These fuzzers leverage dbus-daemon and a live avahi-daemon within the OSS-Fuzz environment to test real-world CGo state transitions and asynchronous event handling.
• Pure Go DNS Decoding: Implemented targeted fuzzing for DNSDecodeA, DNSDecodeAAAA, and DNSDecodeTXT functions to validate resource record parsing without external dependencies.
• Architectural Cleanup: Removed deprecated local runner scripts and non-standard in-code seed management, strictly following the patterns observed in the ipp-usb and goipp projects.
• Binary Portability: Enhanced oss_fuzz_build.sh with robust RPATH patching using patchelf to ensure binary compatibility across different container execution environments.

Implementation Steps:

1. Header Standardization: Updated all existing and new fuzzer sources to include standard OpenPrinting copyright headers.
2. Logic Isolation: Refactored fuzzers to utilize external seed corpuses managed via the build script, ensuring a clean and maintainable codebase.
3. Graceful Degradation: Implemented fallback logic in stateful fuzzers that detects the presence of the avahi-daemon, allowing tests to skip gracefully in restrictive environments while remaining fully functional for intensive fuzzing.
4. Local Validation: Conducted extensive verification using the OSS-Fuzz emulator with AddressSanitizer (ASAN) enabled, achieving millions of iterations across all 11 harnesses with 0 detected crashes or leaks.

Verified Harnesses:

• fuzz_dns_decode_a
• fuzz_dns_decode_aaaa
• fuzz_dns_decode_txt
• fuzz_entry_group
• fuzz_service_browser
• fuzz_client_lifecycle
• fuzz_string_array
• fuzz_domain_normalize
• fuzz_domain_roundtrip
• fuzz_service_name
• fuzz_state_strings