16.3.0

What's Changed

• Bump .NET 11 NuGet packages to preview 5 by @glen-84 in #9965
• Add directive-argument opt-in and code-first directive APIs by @glen-84 in #9966
• Adds supertype narrowing to planner and execution. by @michaelstaib in #9963
• Fix explicit field resolver dropped by named runtime-type binding by @michaelstaib in #9967
• [Nitro CLI] Surface CLI/backend version mismatch on HC0020 by @tobias-tengler in #9968
• Fix file upload FormatException for parameterized Content-Type by @michaelstaib in #9969
• Support @requiresOptIn on directive definitions by @glen-84 in #9970
• Support constant arguments in field selection maps and @key by @glen-84 in #9974
• Fix included conditional selections not being projected by @tobias-tengler in #9818
• Fix internal projection selections leaking into the response by @michaelstaib in #9978
• Optimize shared opt-in introspection resolvers by @glen-84 in #9979
• Fix flaky error-result timeout test by @glen-84 in #9980
• Remove GitHub code-quality coverage upload jobs by @glen-84 in #9983
• Fix flaky Mocha Postgres tests with shared Npgsql helper by @glen-84 in #9981
• Fix flaky MCP adapter activity snapshot tests by @glen-84 in #9982

Full Changelog: 16.2.3...16.3.0