[idea] Lint rules for modelling errors that hit both arms (picker XPath vs entity access, refreshInClient, uncommitted change, empty-value functions, CE2729)

[MendixMau]

The idea: 4–5 modelling errors happened independently in both arms, so they come from the spec or the platform, not from the authoring tool. Proposed rules:

1. A picker XPath that reads rows the current role cannot read under entity access.
2. A page-button microflow that changes objects shown on the page, without refreshInClient.
3. A change without a commit at the end of a microflow called from a timer or workflow.
4. addDays or trim on a possibly empty attribute.
5. Navigation with no logout item, or a home page the role cannot read (CE2729).

Add them to learned-detection-gaps.md now and file them as mxcli lint requests.

Field evidence: contrib/inbox/2026-09-29-lint-rules-recurring-modelling-errors.md (#165). Hypothesis: these rules would prevent ~6–8 of the ~75 combined defects.

Rough size: one skill, plus upstream requests.