Refactor unlockers command structure and add quiet flag to list command

- Rename 'unlockers' command to 'unlocker' for consistency
- Move all unlocker subcommands (list, add, remove) under single 'unlocker' command
- Add --quiet/-q flag to 'secret list' for scripting support
- Update documentation and tests to reflect command changes

The quiet flag outputs only secret names without headers or formatting,
making it ideal for shell script usage like: secret get $(secret list -q | head -1)

Makefile

@@ -11,8 +11,7 @@ default: check
 
 build: ./secret
 
-# Simple build (no code signing needed)
-./secret:
+./secret: ./internal/*/*.go ./pkg/*/*.go ./cmd/*/*.go ./go.*
 	go build -v -ldflags "$(LDFLAGS)" -o $@ cmd/secret/main.go
 
 vet:
@@ -30,7 +29,7 @@ lint:
 check: build test
 
 # Build Docker container
-docker: 
+docker:
 	docker build -t sneak/secret .
 
 # Run Docker container interactively