[Feature] Decouple SeaTunnel Client and Server SEATUNNEL_HOME

1. Current Problem

Today SeaTunnel assumes that client and server nodes use the same SEATUNNEL_HOME path. This creates deployment inflexibility:

• Client : /home/user/seatunnel-client
• Server : /opt/seatunnel-server

When paths differ, code breaks because:

• Client may send its absolute paths to server
• Server expects files at locations that don't exist
• Ops teams forced to use identical paths everywhere

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2. Goal

Allow client and server to use different SEATUNNEL_HOME values, while each maintains the standard directory structure internally:

Client: /home/user/seatunnel-client/
  ├── bin/
  ├── connectors/
  ├── config/
  └── lib/

Server: /opt/seatunnel-server/
  ├── bin/
  ├── connectors/
  ├── config/
  └── lib/

Key principle: Each process resolves paths based on its own SEATUNNEL_HOME, not paths from other nodes.

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3. Requirements

3.1 Core Requirements

1. Client and server can use different root paths
2. Internal structure (connectors/, config/, lib/) remains fixed relative to SEATUNNEL_HOME
3. Client only sends logical job configs (connector names, not absolute paths) to server
4. Each side loads resources from its own directories
5. Full backward compatibility: existing deployments (same path everywhere) work unchanged

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4. Implementation Approach

4.1 Core Principle

Each process (client/server) resolves paths independently based on its own SEATUNNEL_HOME environment variable.

4.2 Key Changes

1. Unified Path Resolution

   • Create a PathResolver utility that reads SEATUNNEL_HOME and resolves standard subdirectories
   • Replace all hardcoded path concatenations with calls to PathResolver

2. Client-Server Communication

   • Client sends logical references (e.g., connector name "kafka-source") in job configs
   • Server resolves connector from its own $SEATUNNEL_HOME/connectors/ directory
   • Never pass absolute filesystem paths from client to server

3. Backward Compatibility

   • If SEATUNNEL_HOME is same everywhere (current setup), behavior unchanged
   • No configuration file changes needed

4.3 What Needs Fixing

Identify and fix code that:

• Assumes client and server have same SEATUNNEL_HOME
• Passes absolute paths from client to server (e.g., in job submission)
• Hardcodes path concatenation like System.getenv("SEATUNNEL_HOME") + "/connectors"