Add 18 community AL/BC patterns across style, data-modeling, web-services, appsource, breaking-changes, performance, and testing

Contributed by CURABIS ApS, generalized from patterns observed across real AppSource/PTE development. Each article follows the knowledge file format (frontmatter, Description/Best Practice/Anti Pattern, sibling .good.al/.bad.al samples).

microsoft/knowledge/style/binary-choice-must-be-boolean.md

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+---
+bc-version: [all]
+domain: style
+keywords: [boolean, option, yes-no, magic-number, variable-typing, field-typing]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# Binary yes/no choices must be typed as Boolean, not Option or Integer
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+
+When a field or variable represents exactly two states — yes/no, on/off, active/inactive, blocked/not blocked — it should be typed `Boolean`. Modeling that same two-state choice as an `Option`/`Enum` with two members, or as an `Integer` with two magic-number values, adds a layer of indirection a reader has to resolve before understanding the code, and it invites a multi-branch check where a simple `if X then` would do. This is distinct from a genuine multi-value choice with more than two named states, which legitimately calls for `Enum` — the line is the state count.
+
+## Best Practice
+
+Type a true two-state field or variable as `Boolean` and branch on it directly.
+
+See sample: `binary-choice-must-be-boolean.good.al`.
+
+## Anti Pattern
+
+Modeling a yes/no choice as an `Option` with two members, or as an `Integer` with magic-number values, forces every caller to remember which value means what and leaves room for a meaningless third value.
+
+See sample: `binary-choice-must-be-boolean.bad.al`.