feat: add bot_optional and user_optional scopes to app manifest

[mwbrooks]

Changelog

Add support for optional OAuth scopes (bot_optional and user_optional) in the app manifest schema.

Summary

This pull request adds two new optional properties to the manifest schema: oauth_config.scopes.bot_optional and oauth_config.scopes.user_optional. These allow apps to declare optional OAuth scopes for both bot and user tokens.

Notes

• The new fields use omitempty, so they are fully backwards-compatible and only serialized when set.
• We may need to update the developerInstall endpoint to accept the optional scopes. We can investigate this next.

Testing

# Create a Starter App
$ ./bin/slack create my-app -t https://github.com/slack-samples/bolt-js-starter-template
$ cd my-app/

# Add optional scopes
$ vim manifest.json
# Replace "oauth_config: { .... }" with:

    "oauth_config": {
        "scopes": {
            "user": [
                "search:read.public",
                "search:read.private",
                "search:read.mpim",
                "search:read.im",
                "search:read.files",
                "search:read.users",
                "chat:write",
                "channels:history",
                "groups:history",
                "mpim:history",
                "im:history",
                "canvases:read",
                "canvases:write",
                "users:read",
                "users:read.email",
                "reactions:write"
            ],
            "user_optional": [
                "search:read.private",
                "search:read.mpim",
                "search:read.im",
                "search:read.files",
                "chat:write",
                "groups:history",
                "mpim:history",
                "im:history",
                "canvases:read",
                "canvases:write"
            ],
            "bot": [
                "app_mentions:read",
                "assistant:write",
                "im:history",
                "channels:history",
                "chat:write",
                "commands"
            ],
            "bot_optional": [
                "canvases:read"
            ]
        }
    },

# Confirm production CLI is missing optional scopes
$ lack-prod manifest info --source local
# → Confirm no `user_optional` or `bot_optional` scopes

# Confirm new CLI includes the optional scopes
$ ../bin/slack manifest info --source local

# Confirm new CLI installs the app
$ ../bin/slack run

# Cleanup
$ lack delete -f

Requirements

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 71.27%. Comparing base (783ac1a) to head (0e5c9b3).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #517      +/-   ##
==========================================
+ Coverage   71.25%   71.27%   +0.02%     
==========================================
  Files         222      222              
  Lines       18682    18682              
==========================================
+ Hits        13311    13316       +5     
+ Misses       4190     4187       -3     
+ Partials     1181     1179       -2     

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