feat: implement contextual separator coercion

Fixes the critical issue where refaktor-core was renamed to
smart_search_and_replace-core (mixed separators) instead of
smart-search-and-replace-core (consistent hyphens).

Key features:
- Automatic style detection (kebab-case, snake_case, PascalCase, etc.)
- Context-aware coercion maintains container naming conventions
- Smart file extension handling for proper style detection
- Case-insensitive multi-occurrence replacement
- Dot-case exclusion by default (risky for extensions)
- Integration with both content matches and file/directory renames

Comprehensive test coverage includes:
- Critical test case: refaktor-core → smart-search-and-replace-core
- Various container styles and edge cases
- End-to-end repository scanning with coercion
- File/directory rename coercion
- Content match coercion within code

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ndbroadbent

README.md

@@ -2,7 +2,20 @@
 
 Smart search & replace for code and files with case-aware transformations and built-in undo/redo.
 
-## Demo: Refaktor Refactoring Itself! 🤯
+- CLI tool
+- Extension for VS Code and Cursor _(coming soon)_
+- MCP server for AI integrations _(coming soon)_
+
+## Features
+
+- Case-aware transformations (snake_case, kebab-case, camelCase, PascalCase, UPPER_SNAKE_CASE)
+- File and directory renaming
+- Plan / apply workflow for safety during large refactorings
+- Built-in undo/redo with history tracking (separate to git history)
+  - Perform a large refactor safely without needing to commit anything first
+- Cross-platform support (Linux, macOS, Windows)
+
+## Demo
 
 Watch Refaktor rename itself to `smart_search_and_replace`, then use the renamed binary to change it back:
 
@@ -30,16 +43,7 @@ cargo build --release
 ./target/release/refaktor --help
 ```
 
-This demonstrates Refaktor's power: it can rename entire projects including all code references, file names, directory names, and even the binary itself - all while maintaining perfect consistency across different naming conventions!
-
-## Features
-
-- Case-aware transformations (snake_case, kebab-case, camelCase, PascalCase, UPPER_SNAKE_CASE)
-- File and directory renaming
-- Built-in undo/redo with history tracking
-- Cross-platform support (Linux, macOS, Windows)
-- VS Code extension
-- MCP server for AI integrations
+This demonstrates Refaktor's power: it can rename entire projects including all code references, file names, and directory names - all while maintaining perfect consistency across different naming conventions.
 
 ## Build Status
 
@@ -75,4 +79,4 @@ cargo llvm-cov --package refaktor-core
 
 ## License
 
-MIT License - Copyright (c) 2025 DocSpring
+MIT License - Copyright (c) 2025 DocSpring

refaktor-cli/src/main.rs

@@ -398,6 +398,7 @@ fn handle_plan(
         rename_files,
         rename_dirs,
         plan_out: plan_out.clone(),
+        coerce_separators: refaktor_core::scanner::CoercionMode::Auto,  // TODO: make configurable
     };
 
     // Scan the repository