[To dev/1.3] Fix floating-point sentinel misuse in KDTree and SDT (#18302)

[Caideyipi]

Backport #18302 to dev/1.3.

This initializes SDT slope doors with infinities, computes KDTree bounds across all points with correct floating-point sentinels, and uses NaN for the integration-test NULL sentinel so real zero values remain distinguishable.

Backport adaptation:

• dev/1.3 does not contain Fix overflow edge cases in query utilities #17875, so SwingingDoorTrendingFilterTest includes only the two sentinel regression cases from Fix floating-point sentinel misuse in KDTree and SDT #18302 and omits the unrelated extreme-timestamp case.

Tests:

• mvn spotless:apply -pl iotdb-core/node-commons,iotdb-core/datanode,integration-test -P with-integration-tests
• mvn test -pl iotdb-core/node-commons -Dtest=KDTreeUtilTest
• mvn test -pl iotdb-core/datanode -Dtest=SwingingDoorTrendingFilterTest

Not run:

• IoTDBUDTFBuiltinFunctionIT#testMasterRepair. The dev/1.3 reactor is blocked before the integration-test module by pre-existing generated-source issues: client-go RAT failures and a generated Thrift/API version mismatch.