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/sheets/doc.go

@@ -0,0 +1,65 @@
+// Package sheets manages collections of cheat sheets across multiple cheatpaths.
+//
+// The sheets package provides functionality to:
+//   - Load sheets from multiple cheatpaths
+//   - Consolidate duplicate sheets (with precedence rules)
+//   - Filter sheets by tags
+//   - Sort sheets alphabetically
+//   - Extract unique tags across all sheets
+//
+// # Loading Sheets
+//
+// Sheets are loaded recursively from cheatpath directories, excluding:
+//   - Hidden files (starting with .)
+//   - Files in .git directories
+//   - Files with extensions (sheets have no extension)
+//
+// # Consolidation
+//
+// When multiple cheatpaths contain sheets with the same name, consolidation
+// rules apply based on the order of cheatpaths. Sheets from earlier paths
+// override those from later paths, allowing personal sheets to override
+// community sheets.
+//
+// Example:
+//
+//	cheatpaths:
+//	  1. personal: ~/cheat
+//	  2. community: ~/cheat/community
+//
+//	If both contain "git", the version from "personal" is used.
+//
+// # Filtering
+//
+// Sheets can be filtered by:
+//   - Tags: Include only sheets with specific tags
+//   - Cheatpath: Include only sheets from specific paths
+//
+// Key Functions
+//
+//   - Load: Loads all sheets from the given cheatpaths
+//   - Filter: Filters sheets by tag
+//   - Consolidate: Merges sheets from multiple paths with precedence
+//   - Sort: Sorts sheets alphabetically by title
+//   - Tags: Extracts all unique tags from sheets
+//
+// Example Usage
+//
+//	// Load sheets from all cheatpaths
+//	allSheets, err := sheets.Load(cheatpaths)
+//	if err != nil {
+//	    log.Fatal(err)
+//	}
+//
+//	// Consolidate to handle duplicates
+//	consolidated := sheets.Consolidate(allSheets)
+//
+//	// Filter by tag
+//	filtered := sheets.Filter(consolidated, "networking")
+//
+//	// Sort alphabetically
+//	sheets.Sort(filtered)
+//
+//	// Get all unique tags
+//	tags := sheets.Tags(consolidated)
+package sheets