devkit avs call fails.

devkit avs call `--signature="(uint256,string)" args='(5,"hello")'`
```
Incorrect Usage: flag provided but not defined: -signature

NAME:
devkit avs call - Submits tasks to the local devnet, triggers off-chain execution, and aggregates results

USAGE:
devkit avs call [command options]

COMMANDS:
help, h Shows a list of commands or help for one command

OPTIONS:
--verbose, -v Enable verbose logging (default: false)
--enable-telemetry Enable telemetry collection on first run without prompting (default: false)
--disable-telemetry Disable telemetry collection on first run without prompting (default: false)
--help, -h show help
2025/07/16 14:04:58 flag provided but not defined: -signature
```
Also the autocomplete on zsh seems broken. When I type `devkit avs call --sig` and press tab, I get
```
devkit avs call --sigpanic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x30 pc=0x10501b3b8]

goroutine 1 [running]:
flag.(*FlagSet).Args(...)
/opt/homebrew/Cellar/go/1.24.2/libexec/src/flag/flag.go:741
github.com/urfave/cli/v2.(*Context).Args(...)
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/context.go:167
github.com/urfave/cli/v2.checkCompletions(0x1063d8a00?)
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/help.go:467 +0x28
github.com/urfave/cli/v2.(*Command).Run(0x1063d8a00, 0x140005cc840, {0x140005cafc0, 0x3, 0x3})
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/command.go:160 +0xf0
github.com/urfave/cli/v2.(*Command).Run(0x1063da000, 0x140005cc700, {0x140005cc740, 0x4, 0x4})
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/command.go:269 +0x828
github.com/urfave/cli/v2.(*Command).Run(0x140000fd1e0, 0x140005cc500, {0x140000322a0, 0x5, 0x6})
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/command.go:269 +0x828
github.com/urfave/cli/v2.(*App).RunContext(0x140001ab000, {0x105ce9940, 0x140005d40a0}, {0x140000322a0, 0x6, 0x6})
/Users/mm/go/pkg/mod/github.com/urfave/cli/v2@v2.27.6/app.go:333 +0x51c
main.main()
/Users/mm/devkit-cli/cmd/devkit/main.go:63 +0x244
```

Inizia da cmd/devkit/main.go, intorno alla riga 63, e riproduci la chiamata avs e il comando di completamento zsh segnalati. Segui la registrazione del comando avs call e il percorso di completamento mostrato nello stack trace di urfave/cli; il lavoro è terminato quando l'opzione signature viene gestita e premere tab dopo --sig non provoca più un panic.

Scritto dal modello di indicizzazione a partire dal testo della issue.