[FLUSS-3553][build] Fix shaded Jackson classes leaking into uber-jars

[Jackeyzhe]

Summary

fluss-shaded-jackson contains unshaded Multi-Release JAR (MRJ) entries under
META-INF/versions/*/com/fasterxml/jackson/core/io/doubleparser/ (and sibling
parser dirs). The Maven Shade Plugin only relocates base-path classes, not MRJ
entries. These leak into uber-jars (fluss-client, fluss-flink-*) and can
shadow downstream apps' jackson-core 2.16+, causing NoSuchMethodError: JsonToken._updateToken.

Root Cause

The shade plugin's relocation (<relocation>) only transforms classes at their
base path (com/fasterxml/jackson/...). Multi-Release JAR entries stored under
META-INF/versions/<java-version>/com/fasterxml/jackson/... are not relocated
and remain at their original package path. When these entries are packaged into
uber-jars, they can win the class-loading race against the consumer's own
jackson-core dependency.

Fix

Add <exclude>META-INF/versions/**/com/fasterxml/**</exclude> to the root
pom.xml global shade filter (<artifact>*</artifact>). This cascades to ALL
modules via combine.children="append".

The base FastDoubleParser implementation (at the relocated path) is sufficient
for all Java versions; the MRJ entries are only performance optimizations for
specific JDK versions.

Test Plan

• Before fix: 5 uber-jars (fluss-client + fluss-flink-1.18/1.19/1.20/2.2/tiering)
  contain unshaded jackson MRJ entries
• After fix: 0 unshaded jackson entries in all 5 uber-jars
• ./mvnw -pl fluss-common test passes (267 tests, 0 failures)
• ./mvnw spotless:check passes
• git diff --check clean

Files Changed

• pom.xml (+11 lines: 1 exclude rule in global shade filter)

🤖 AI-assisted changes - reviewed by human developer

Closes #3553

[Jackeyzhe]

Gentle ping for review when anyone has a moment. All CI checks are green, and the fix is a single 11-line exclusion rule in the root pom.xml global shade filter.

Quick recap: fluss-shaded-jackson ships unshaded Multi-Release JAR entries (META-INF/versions//com/fasterxml/) that the Maven Shade Plugin doesn't relocate. These leak into every uber-jar (fluss-client, fluss-flink-*) and can shadow downstream jackson-core 2.16+, causing NoSuchMethodError: JsonToken._updateToken at runtime.

The fix adds one to the global * filter, which cascades to all modules via combine.children="append". Verified: 0 unshaded jackson entries in all 5 previously-affected uber-jars; fluss-common tests pass (267, 0 failures).

Would appreciate it if @wuchong, @fresh-borzoni, or @Yohahaha could take a look when convenient. Happy to make adjustments if anything needs changing. Thanks!