fix: standardise on CREATE OR MODIFY — remove/deprecate CREATE OR REPLACE variants

[ako]

Background

Two upsert variants exist in MDL:

• CREATE OR MODIFY — updates the existing document in-place, preserving its UUID/ID. References from other documents (navigation, microflow calls, page references) remain intact.
• CREATE OR REPLACE — deletes the existing document and creates a new one with a fresh UUID. This silently breaks any in-project reference to the old UUID.

Problem

CREATE OR REPLACE is actively unsafe for any document that is referenced from elsewhere in the project. A page replaced this way gets a new ID; any microflow with a show page action targeting the old ID becomes a dangling reference that only surfaces when Studio Pro opens the file.

Additionally, the error message on plain CREATE MICROFLOW currently reads:

microflow 'Module.Name' already exists (use create or replace to overwrite)

This steers users toward the unsafe variant. Microflows don't even have CREATE OR REPLACE syntax — only CREATE OR MODIFY — so the message is both misleading and wrong.

Proposed change

1. Standardise on CREATE OR MODIFY as the idempotent upsert for all document types. Where a type currently only has CREATE OR REPLACE (JSON structure, image collection, published REST service, business event service), add CREATE OR MODIFY and consider deprecating OR REPLACE.
2. Fix the error message in cmd_microflows_create.go to say use create or modify to overwrite instead of use create or replace.
3. Document the distinction in MDL_QUICK_REFERENCE.md and the relevant skill files: OR MODIFY preserves UUID (safe for referenced documents), OR REPLACE does not (avoid unless the document is guaranteed unreferenced).

Affected files

• mdl/executor/cmd_microflows_create.go — misleading error message (line ~73)
• Grammar and executor for types that only have OR REPLACE: JSON structure, image collection, published REST service, business event service
• docs/01-project/MDL_QUICK_REFERENCE.md

[github-actions]

Issue Triage

Summary:
The issue requests standardising on CREATE OR MODIFY as the safe upsert for all document types, fixing a misleading error message, and documenting the UUID‑preserving vs. UUID‑changing behavior.

Checklist for feature request

Required info	Present?	Details
Use case – why the feature is needed, what problem it solves	✅	Describes the unsafe nature of CREATE OR REPLACE and the misleading error message.
Proposed syntax or behavior (if applicable)	✅	Lists three concrete changes: adopt CREATE OR MODIFY universally, fix the error message, and update documentation.
Mendix version relevance (if version‑specific)	❌	No mention of whether this applies to specific Mendix versions or is version‑agnostic.

Missing information
Could you let us know if this change is relevant to particular Mendix versions (e.g., only affects 10.x, 9.x, etc.) or if it applies across all supported versions? Once we have that detail, the issue will be complete. Thank you!

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