Add IoTDB Edge distribution: ConfigNode + DataNode merged in one JVM

[JackieTien97]

Motivation

IoTDB's default configuration and startup parameters assume the machine is exclusively dedicated to IoTDB (heap sized from machine memory: DataNode 50% uncapped, ConfigNode 30% capped at 8G). On edge machines that also run other processes this is far too aggressive. This PR adds an IoTDB Edge distribution — apache-iotdb-edge-${version}-all-bin — whose defaults target a total process RSS of ~512 MB, validated on Raspberry Pi 4B class devices.

Changes

New entry point (one JVM, both nodes)

• org.apache.iotdb.edge.EdgeNode (in iotdb-core/confignode, which already depends on iotdb-server): bootstraps the ConfigNode on a background thread, waits for its internal RPC port to accept connections, then starts the DataNode in the same JVM. This saves a whole JVM's fixed overhead (metaspace, code cache, GC structures, thread stacks) — ~140 MB measured. All logs go through i18n'd ConfigNodeMessages constants (en/zh in key parity).
• Shared-singleton audit: ports / data dirs / JMX bean names don't collide; the internal MetricService singleton is safe because both node metric levels default to OFF in the edge config.

One pair of lifecycle scripts only

• sbin/start-edge.sh / stop-edge.sh (+ Windows start-edge.bat / stop-edge.bat). No separate ConfigNode/DataNode scripts in this package. start-edge.sh sets CONFIGNODE_HOME explicitly so the ConfigNode resolves its directories against the installation dir rather than the process working directory (a real pitfall found during testing).
• conf/edge-env.sh (+ .bat): fixed small JVM budget, overridable via environment variables — Xmx 224M / Xms 64M, direct 96M, metaspace 160m, SerialGC, Xss320k, ActiveProcessorCount=2.

Edge-tuned defaults (conf/iotdb-system.properties in the edge package only)

• Small fixed thread pools (query 2, compaction 2/1/1, flush 2, MPP exchange 2/2, …) instead of CPU-core-based sizing.
• 1M WAL buffer, 4M tsfile write buffer, 128M compaction target file size.
• schema/data_region_group_extension_policy=CUSTOM with 1 region group per database, series_slot_num=1.
• Compaction throughput capped at 8 MB/s to stay polite on shared disks; cn/dn_metric_level=OFF.

Packaging

• distribution/src/assembly/edge.xml + conf-edge/ resources; the default mvn package -pl distribution -am build now also produces apache-iotdb-edge-${version}-all-bin (dir/zip + sha512), alongside the unchanged regular packages.
• all.xml excludes the edge scripts from the regular all-bin distribution (same pattern as ainode), so regular packages are byte-identical in layout to before.

Validation

Full test report (machine specs incl. Raspberry Pi 4B): https://timechor.feishu.cn/docx/Hlf0dyQ4FoQsf4xEFnSc4TTknIg?from=from_copylink

• Raspberry Pi 4B (4×Cortex-A72/8G/SD): ≥ 10,000 series across tree-aligned / tree-non-aligned / table models, 30-min soak per shape, zero failed points, zero OOM; idle RSS ~194 MB.
• Edge package smoke on Pi: start-edge → CLI insert/select → stop-edge, clean shutdown verified.
• mvn package -pl distribution -am -DskipTests passes; all 37 Java modules compile under -P with-zh-locale (i18n keys in en/zh parity).

[codecov]

Codecov Report

❌ Patch coverage is 0% with 36 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.23%. Comparing base (6aec4b8) to head (f2535c3).

Files with missing lines	Patch %	Lines
.../src/main/java/org/apache/iotdb/edge/EdgeNode.java	0.00%	36 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #18538      +/-   ##
============================================
- Coverage     42.23%   42.23%   -0.01%     
  Complexity      413      413              
============================================
  Files          5409     5410       +1     
  Lines        389925   389961      +36     
  Branches      50970    50973       +3     
============================================
+ Hits         164685   164689       +4     
- Misses       225240   225272      +32     

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