fix: store Boolean constant values as "True"/"False" (mendixlabs/mxcli#1321)

[ako]

Fixes mendixlabs#1321.

Problem

Reported: "create constant with Type: Boolean stores the literals true and True as the string "true". Studio Pro stores a Boolean default as "True" or "False"… Studio Pro's constant dialog shows a stored "true" as False, while the runtime reads it as true."

Two write paths had this defect:

• Constant default (create constant, create or modify constant): createConstant turned the parsed literal into text with fmt.Sprintf("%v"), so a boolean was written as Go's lowercase "true"/"false". Only a quoted 'True' was copied as written.
• Configuration override (alter settings constant @M.Flag value true): the value was stored exactly as typed, without checking the constant's type.

describe constant reads the value without caring about case, so the two forms looked the same and only the stored file showed the difference.

Fix

• storedConstantDefault (mdl/executor/cmd_constants.go) converts any capitalisation of true/false to "True"/"False" for Boolean constants. Values of other types are left unchanged.
• alterSettingsConstant (mdl/executor/cmd_settings.go) looks up the constant's type with settingsConstantType and uses the same helper. A String constant set to 'true' keeps lowercase "true". If the constant can't be found, the value is stored as written.

Evidence

Tests written first (mdl/executor/cmd_constant_boolean_default_test.go, using MockBackend). Each failed with the reported symptom before its fix and passes after it:

• create constant: 5 of 6 spellings failed (e.g. DefaultValue: true stored as "true", want "True"). The quoted 'True' control passed.
• create or modify constant: failed with stored as "true".
• alter settings constant: 3 of 5 cases failed (value true stored as "true", value FALSE stored as "FALSE"). The two controls, already 'True' and a String constant, passed.

Stored on disk: I ran the scripts against a copy of testdata/pedapp and read the stored files.

statement	before	after
DefaultValue: true / True	"true"	"True"
DefaultValue: false	"false"	"False"
value true / value 'true' (Boolean)	"true"	"True"
value 'true' (String constant)	"true"	"true"

Not verified with Mendix tools: I didn't run mx check, the runtime or Studio Pro. Per the report, mx check flags neither spelling and the runtime reads both as true; only Studio Pro's dialog shows the difference, and Studio Pro can't run here. That "True"/"False" is the right form rests on the reporter's Studio Pro 11.12.4 measurement; the repo has no Studio Pro-made Boolean constant to compare against.

Also in this PR

• Bug test mdl-examples/bug-tests/1321-boolean-constant-default-case.mdl; passes mxcli check and make check-mdl.
• Finding appended to .claude/skills/fix-issue/findings/mdl-executor.jsonl; make check-findings passes.
• make build, make test and make lint pass.

🤖 Generated with Claude Code

https://claude.ai/code/session_018KhC7qZthbY6TNuUTqURmt