Use MemoizedCheckedSupplier for COPY TO folder manager & keep compatibility with another branch

[shuwenwei]

Description

This PR updates TierManager to lazily initialize the COPY TO target FolderManager with MemoizedCheckedSupplier, so COPY TO target directories are not created during startup or tier initialization when the COPY TO feature is not used.

It also keeps several query execution context and DataNode service visibility changes for compatibility with another branch, including passing an optional memory reservation manager through column transformer context construction.

Key Changes

• Changed COPY TO target folder manager initialization in TierManager to use MemoizedCheckedSupplier.
• Avoided creating COPY TO target directories unless the COPY TO target folder is actually requested.
• Kept compatibility changes for another branch by adding optional MemoryReservationManager plumbing to column transformer contexts.
• Excluded templates/** from datanode codegen resources.
• Made DataNodeInternalRPCService.impl and dataNodeContext accessible to subclasses.

[sonarqubecloud]

Quality Gate passed

Issues
7 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

❌ Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 39.85%. Comparing base (ce84224) to head (6783932).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...otdb/db/storageengine/rescon/disk/TierManager.java	50.00%	2 Missing ⚠️
...e/plan/planner/DataNodeTableOperatorGenerator.java	0.00%	1 Missing ⚠️
...e/iotdb/db/service/DataNodeInternalRPCService.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17559      +/-   ##
============================================
- Coverage     39.85%   39.85%   -0.01%     
  Complexity     2547     2547              
============================================
  Files          5171     5171              
  Lines        348174   348176       +2     
  Branches      44489    44489              
============================================
  Hits         138767   138767              
- Misses       209407   209409       +2     

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