mcp: appendBoolFlag silently drops explicit false values

[Elvand-Lie]

Bug

appendBoolFlag in pkg/mcp/tools.go only appends the flag when *value == true:

func appendBoolFlag(args []string, flag string, value *bool) []string {
    if value != nil && *value {
        return append(args, flag)
    }
    return args
}

When the AI agent explicitly sends {"push": false}, the pointer is non-nil but the value is false, so the flag is silently dropped. For boolean flags like --push, --remote, and --registry-insecure, there is no way for the MCP client to explicitly disable a flag that was previously set via func.yaml or defaults.

Example scenario:

1. User deploys with --push enabled (value saved in func.yaml)
2. AI agent sends {"push": false} to disable push on the next deploy
3. appendBoolFlag drops the flag entirely
4. func deploy reads func.yaml and pushes anyway

Impact

The MCP client cannot explicitly disable a boolean option that was previously enabled. The underlying CLI supports --push=false to explicitly override defaults, but the MCP layer cannot express that intent.

Fix

When value != nil && !*value, append flag=false (e.g. --push=false) instead of dropping the flag silently.

[Elvand-Lie]

/kind bug

[thonmay]

Hi, I'd like to work on this. The silent drop of explicit false values in appendBoolFlag is a real correctness issue, agents that explicitly set a bool flag to false would have it silently ignored. I have a fix in mind and happy to pick this up if it's free.

[thonmay]

/assign

[Elvand-Lie]

Hey @thonmay I also agreed with the issue. I already have a PR open (#3709) that addresses this doing duplicate PRs generally isn't ideal since maintainers can't be everywhere at once. This one already has a fix linked.

[Elvand-Lie]

/assign

[thonmay]

Closing my PR #3746 in favor of #3709. Should have checked open PRs before opening mine. Thanks @Elvand-Lie.