chore: bump version to 4.5.0

Bug fixes:
- Fix inverted pager detection logic (returned error instead of path)
- Fix repo.Clone ignoring destination directory parameter
- Fix sheet loading using append on pre-sized slices
- Clean up partial files on copy failure
- Trim whitespace from editor config

Security:
- Add path traversal protection for cheatsheet names

Performance:
- Move regex compilation outside search loop
- Replace string concatenation with strings.Join in search

Build:
- Remove go:generate; embed config and usage as string literals
- Parallelize release builds
- Add fuzz testing infrastructure

Testing:
- Improve test coverage from 38.9% to 50.2%
- Add fuzz tests for search, filter, tags, and validation

Documentation:
- Fix inaccurate code examples in HACKING.md
- Add missing --conf and --all options to man page
- Add ADRs for path traversal, env parsing, and search parallelization
- Update CONTRIBUTING.md to reflect project policy

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,117 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Common Development Commands
+
+### Building
+```bash
+# Build for your architecture
+make build
+
+# Build release binaries for all platforms
+make build-release
+
+# Install cheat to your PATH
+make install
+```
+
+### Testing and Quality Checks
+```bash
+# Run all tests
+make test
+go test ./...
+
+# Run a single test
+go test -run TestFunctionName ./internal/package_name
+
+# Generate test coverage report
+make coverage
+
+# Run linter (revive)
+make lint
+
+# Run go vet
+make vet
+
+# Format code
+make fmt
+
+# Run all checks (vendor, fmt, lint, vet, test)
+make check
+```
+
+### Development Setup
+```bash
+# Install development dependencies (revive linter, scc)
+make setup
+
+# Update and verify vendored dependencies
+make vendor-update
+```
+
+## Architecture Overview
+
+The `cheat` command-line tool is organized into several key packages:
+
+### Command Layer (`cmd/cheat/`)
+- `main.go`: Entry point, argument parsing, command routing
+- `cmd_*.go`: Individual command implementations (view, edit, list, search, etc.)
+- Commands are selected based on docopt parsed arguments
+
+### Core Internal Packages
+
+1. **`internal/config`**: Configuration management
+   - Loads YAML config from platform-specific paths
+   - Manages editor, pager, colorization settings
+   - Validates and expands cheatpath configurations
+
+2. **`internal/cheatpath`**: Cheatsheet path management
+   - Represents collections of cheatsheets on filesystem
+   - Handles read-only vs writable paths
+   - Supports filtering and validation
+
+3. **`internal/sheet`**: Individual cheatsheet handling
+   - Parses YAML frontmatter for tags and syntax
+   - Implements syntax highlighting via Chroma
+   - Provides search functionality within sheets
+
+4. **`internal/sheets`**: Collection operations
+   - Loads sheets from multiple cheatpaths
+   - Consolidates duplicates (local overrides global)
+   - Filters by tags and sorts results
+
+5. **`internal/display`**: Output formatting
+   - Writes to stdout or pager
+   - Handles text formatting and indentation
+
+6. **`internal/repo`**: Git repository management
+   - Clones community cheatsheet repositories
+   - Updates existing repositories
+
+### Key Design Patterns
+
+- **Filesystem-based storage**: Cheatsheets are plain text files
+- **Override mechanism**: Local sheets override community sheets with same name
+- **Tag system**: Sheets can be categorized with tags in frontmatter
+- **Multiple cheatpaths**: Supports personal, community, and directory-scoped sheets
+
+### Sheet Format
+
+Cheatsheets are plain text files optionally prefixed with YAML frontmatter:
+```
+---
+syntax: bash
+tags: [ networking, ssh ]
+---
+# SSH tunneling example
+ssh -L 8080:localhost:80 user@remote
+```
+
+### Working with the Codebase
+
+- Always check for `.git` directories and skip them during filesystem walks
+- Use `go-git` for repository operations, not exec'ing git commands
+- Platform-specific paths are handled in `internal/config/paths.go`
+- Color output uses ANSI codes via the Chroma library
+- Test files use the `internal/mock` package for test data