feat(dvb): improve CLI developer experience

[qj0r9j0vc2]

Summary

• Add global --yes/-y and --non-interactive flags for CI/script-friendly usage
• Consolidate dvb start/dvb stop into dvb node start/stop/restart --all
• Add dvb provision --quick/-q for fast provisioning with smart defaults
• Auto-set context after dvb provision
• Add dvb completion [shell] for bash/zsh/fish/powershell
• Add -o json output on dvb list and dvb node list
• Centralize daemon-not-running error handling via requireDaemon()
• Gate all interactive pickers (node, devnet) on IsNonInteractive()

Test plan

• go build ./cmd/dvb/ passes
• go test ./cmd/dvb/... passes
• go vet ./cmd/dvb/... passes
• Manual: dvb --non-interactive node restart returns error with available nodes
• Manual: dvb node start --all starts all nodes
• Manual: dvb provision -q creates devnet with defaults
• Manual: dvb delete my-devnet -y skips confirmation
• Manual: dvb completion zsh outputs completion script