fix: remove cached mcpClient in diagnostic tracking to prevent stale references (#727)

* fix: remove cached mcpClient in diagnostic tracking to prevent stale references

Resolves TODO comment about not caching the connected mcpClient since it can change.

Changes:
- Remove cached mcpClient field from DiagnosticTrackingService
- Add currentMcpClients storage to track active clients
- Update beforeFileEdited, getNewDiagnostics, and ensureFileOpened to accept client parameter
- Add backward-compatible methods to maintain existing API
- Update all callers to use new methods
- Add comprehensive test coverage

This prevents using stale MCP client references during reconnections,
making diagnostic tracking more reliable.

Fixes #TODO

* docs: add my contributions section to README

Add fork-specific section highlighting:
- Diagnostic tracking enhancement (PR #727)
- Technical skills demonstrated
- Links to original project and my work
- Professional contribution showcase

* revert: remove README.md contributions section to comply with reviewer request

- Remove 'My Fork & Contributions' section from README.md
- Keep README.md focused on original project documentation
- Maintain clean, project-focused README as requested by reviewer

src/tools/FileEditTool/FileEditTool.ts

@@ -422,7 +422,7 @@ export const FileEditTool = buildTool({
       activateConditionalSkillsForPaths([absoluteFilePath], cwd)
     }
 
-    await diagnosticTracker.beforeFileEdited(absoluteFilePath)
+    await diagnosticTracker.beforeFileEditedCompat(absoluteFilePath)
 
     // Ensure parent directory exists before the atomic read-modify-write section.
     // These awaits must stay OUTSIDE the critical section below — a yield between

src/tools/FileWriteTool/FileWriteTool.ts

@@ -244,7 +244,7 @@ export const FileWriteTool = buildTool({
     // Activate conditional skills whose path patterns match this file
     activateConditionalSkillsForPaths([fullFilePath], cwd)
 
-    await diagnosticTracker.beforeFileEdited(fullFilePath)
+    await diagnosticTracker.beforeFileEditedCompat(fullFilePath)
 
     // Ensure parent directory exists before the atomic read-modify-write section.
     // Must stay OUTSIDE the critical section below (a yield between the staleness