feat(lsp): add Rename Symbol support

[amondnet]

Summary

Implements LSP Rename Symbol support (textDocument/prepareRename and textDocument/rename) for the @pleaseai/code-lsp package.

Changes

• Add type schemas (TextEdit, WorkspaceEdit, PrepareRenameResult) with Zod validation
• Add prepareRename() method to validate rename at position
• Add rename() method to perform symbol rename
• Add normalization for both changes and documentChanges WorkspaceEdit formats
• Add rename capability (prepareSupport: true) to client initialization
• Update CLAUDE.md documentation with new methods

Architecture Decisions (from Serena reference)

• First successful result pattern: Only one LSP server typically owns a symbol's rename, so return first non-null result
• WorkspaceEdit normalization: Normalize documentChanges format to changes for consistent handling
• PrepareRenameResult: Support all three LSP formats (Range, {range, placeholder}, {defaultBehavior})

Test plan

• 12 unit tests for type schema validation
• 10 integration tests for prepareRename/rename LSP requests
• Tests cover valid rename, invalid positions, parameter rename, and disabled manager

Closes #18

[codecov]

Codecov Report

❌ Patch coverage is 9.19540% with 158 lines in your changes missing coverage. Please review.
✅ Project coverage is 29.72%. Comparing base (e60e5c0) to head (764dfc9).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/lsp/src/index.ts	8.67%	158 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #19      +/-   ##
==========================================
- Coverage   31.79%   29.72%   -2.07%     
==========================================
  Files           4        4              
  Lines        1730     1904     +174     
==========================================
+ Hits          550      566      +16     
- Misses       1180     1338     +158     

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