feat: update acronym to 'Hushing' and fix backup creation bug

- Update SHUSH acronym from 'Hiding' to 'Hushing' (better reflects removal)
- Fix critical error handling bug in file backup creation using io.Copy
- Remove golangci-lint references from Makefile and CLAUDE.md
- Update README, LLM guide, and CLI description with new acronym
- Create TASKS.md to track project improvements

cmd/shush/main.go

@@ -17,7 +17,7 @@ var version = "0.2.1"
 func main() {
 	var cliArgs types.CLI
 	kong.Parse(&cliArgs,
-		kong.Description("Remove comments from source code files"),
+		kong.Description("SHUSH: Sloppily Hushing Unwanted Source-code Heavy"),
 		kong.Vars{"version": version})
 
 	if cliArgs.LLM {