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>

internal/cheatpath/cheatpath.go

@@ -2,6 +2,8 @@
 // management.
 package cheatpath
 
+import "fmt"
+
 // Cheatpath encapsulates cheatsheet path information
 type Cheatpath struct {
 	Name     string   `yaml:"name"`
@@ -9,3 +11,18 @@ type Cheatpath struct {
 	ReadOnly bool     `yaml:"readonly"`
 	Tags     []string `yaml:"tags"`
 }
+
+// Validate ensures that the Cheatpath is valid
+func (c Cheatpath) Validate() error {
+	// Check that name is not empty
+	if c.Name == "" {
+		return fmt.Errorf("cheatpath name cannot be empty")
+	}
+
+	// Check that path is not empty
+	if c.Path == "" {
+		return fmt.Errorf("cheatpath path cannot be empty")
+	}
+
+	return nil
+}