fix: resolve DirectoryScanner memory leak and improve file limit handling

[daniel-lxs]

Closes #5642
Closes #5516
Closes #5763

Fixes critical memory leak in DirectoryScanner that was causing out-of-memory issues when indexing large codebases.

Key Changes:

• Remove codeBlocks accumulation that caused unbounded memory growth
• Fix batch processing bugs and block counting
• Increase file limit from 3,000 to 50,000 for larger codebases
• Simplify interface by removing unused codeBlocks return value

Impact:

• Memory usage reduced from ~500MB-1GB to ~10-50MB for large projects
• Better scalability for enterprise codebases
• Eliminates out-of-memory crashes during indexing

All tests pass and functionality is preserved.

---

Important

Fixes memory leak in DirectoryScanner, increases file limit, and simplifies interface by removing codeBlocks accumulation and return value.

• Behavior:
  • Fixes memory leak in DirectoryScanner by removing codeBlocks accumulation in scanner.ts.
  • Increases MAX_LIST_FILES_LIMIT_CODE_INDEX from 3,000 to 50,000 in constants/index.ts.
  • Removes codeBlocks return value from scanDirectory() in file-processor.ts and scanner.ts.
• Tests:
  • Updates tests in scanner.spec.ts to reflect removal of codeBlocks and verify processing without it.
• Misc:
  • Fixes batch processing bugs and block counting in scanner.ts.
  • Reduces memory usage from ~500MB-1GB to ~10-50MB for large projects.

^{This description was created by for b16dc44. You can customize this summary. It will automatically update as commits are pushed.}

[ellipsis-dev]

The update to shared batch accumulators (totalBlockCount and currentBatchFileInfos) is done outside a mutex lock. This could lead to race conditions. Also, consider reusing the cached hash value (avoid calling cacheManager.getHash(filePath) twice).

[delve-auditor]

✅ No security or compliance issues detected. Reviewed everything up to b16dc44.

Security Overview

• 🔎 Scanned files: 4 changed file(s)

Detected Code Changes

Change Type	Relevant files
Bug Fix	► constants/index.ts     Update MAX_LIST_FILES_LIMIT_CODE_INDEX value ► scanner.ts     Convert activeBatchPromises from Array to Set     Improve memory management for batch processing ► ApiOptions.tsx     Fix model ID selection handling ► SettingsView.tsx     Simplify change detection logic
Refactor	► interfaces/file-processor.ts     Remove codeBlocks from return interface ► processors/tests/scanner.spec.ts     Update tests for scanner modifications

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