Add default value syntax support for bake migration command

[dereuromark]

Summary

• Adds support for specifying default column values in the bake migration command using a new default[value] syntax
• Updated the column grammar in the help text to document the new syntax
• Added comprehensive tests for the new functionality

Examples

# Boolean defaults
bin/cake bake migration AddActiveToUsers active:boolean:default[true]
bin/cake bake migration AddSkipUpdatesToEventImports skip_updates:boolean:default[false]

# Integer defaults
bin/cake bake migration AddCountToProducts count:integer:default[0]

# String defaults (quoted)
bin/cake bake migration AddStatusToOrders status:string:default['pending']

# Combined with other options
bin/cake bake migration AddCountToProducts count:integer:default[0]:unique
bin/cake bake migration AddRoleToUsers role:string?:default['user']

Supported Value Types

• Booleans: true, false
• Integers: 0, 123, -456
• Floats: 1.5, -2.75
• Strings: 'hello' or "world" (quoted)
• Null: null or NULL
• SQL expressions: CURRENT_TIMESTAMP (passed through as-is)

Test plan

• All existing tests pass
• New tests added for parseDefaultValue() method
• New tests added for parseFields() with default values
• New tests added for parseIndexes() with default values
• New tests added for validArguments() with default values
• Code style checks pass

🤖 Generated with Claude Code

[markstory]

Seems reasonable to me.

[dereuromark]

Fun fact:
I only ran into this because claude wanted to "bake":

bin/cake bake migration AddActiveToUsers active:boolean:default[true]

and it errored out.
Only to create it manually then.

So that made me think: Sounds reasonable to expect this API yeah