Regenerate microsoft/knowledge from upstream BCApps instructions

The previous LLM-generated knowledge files contained factual
hallucinations. The most visible was the claim that `FindFirst` /
`FindLast` "forces a full-table scan" on an unfiltered record - it does
not; those APIs return a single row via the current key.

Other inaccuracies the audit found and fixed:

* `FindSet(true)` was described as "taking a LockTable". The correct
  upstream phrasing is that `FindSet(true)` sets
  `ReadIsolation::UpdLock` on the read. UpdLock and LockTable are
  related but distinct mechanisms.
* The list of production-scale tables had been invented beyond the
  upstream source (e.g. "Detailed Cust. Ledg. Entry") without a
  citation. The regenerated list matches the ten tables upstream lists
  with their P95 row counts.
* `SetLoadFields` guidance had been augmented with an extra mechanism
  claim ("the database resolves the filter using the index without
  hydrating the value") not present in upstream.

Approach: full regeneration of `microsoft/knowledge/` from the six
upstream BCApps Code Review instruction files, with Microsoft Learn /
the AL language reference as a secondary source. Every claim in every
regenerated file is anchored to a verbatim upstream quote (or a Learn
URL); the audit trail lives in artifacts/trace-<domain>.json on the
session workspace.

The PR #11 transaction/error-handling cluster is preserved verbatim:

* performance/understand-implicit-transaction-boundary.md
* performance/codeunit-run-as-atomic-sub-operation.{md,good.al,bad.al}
* performance/codeunit-run-requires-prior-commit-inside-transaction.{md,good.al,bad.al}
* performance/use-tryfunction-for-error-catching-not-rollback.{md,good.al,bad.al}
* performance/avoid-commit-inside-loops.{md,good.al,bad.al}
* security/commitbehavior-attribute-scopes-explicit-commits.{md,good.al,bad.al}
* testing/transactionmodel-attribute-governs-test-transactions.{md,good.al,bad.al}

These articles already cite Microsoft Learn and were carefully
cross-referenced; the regeneration skips their topics rather than
duplicating them.

File counts after regeneration:

  performance   35 .md  (5 preserved + 30 new)
  privacy       17 .md
  security      18 .md  (1 preserved + 17 new)
  style         33 .md
  testing        1 .md  (preserved)
  ui            19 .md
  upgrade       18 .md

Total 141 atomic knowledge files, each strictly one rule. All pass
.github/scripts/validate_frontmatter.py with 0 errors and 0 warnings.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

microsoft/knowledge/ui/grid-data-table-heuristic.md

@@ -0,0 +1,28 @@
+---
+bc-version: [all]
+domain: ui
+keywords: [grid, fixed, data-table, heuristic, show-caption, accessibility]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# Grid and fixed-layout data-table heuristic
+
+## Description
+
+Business Central renders `grid()` and `fixed()` layouts in two modes. The mode is chosen automatically by a client heuristic. A grid renders as a **data table** (HTML `<table>` with row/column semantics) only when **all** of the following are true:
+
+- All direct children of the grid/fixed are groups (no loose fields).
+- Every child of every group is a field (no nested groups or other controls).
+- All fields have `ShowCaption = false`.
+
+The heuristic checks field captions only — group `ShowCaption` is not part of the check. A group with a visible caption inside a data-table grid does **not** break the heuristic and is not a violation. However, groups in a data table should also have `ShowCaption = false` for correct visual presentation.
+
+Any grid or fixed layout that does not meet all three conditions renders as a layout table (visual column arrangement, no table semantics).
+
+## Best Practice
+
+If you intend a grid or fixed layout to render as a data table, satisfy all three conditions and verify the resulting markup matches your intent. If you do not need tabular semantics, prefer simple groups over grid or fixed layouts — they reflow better and produce correct semantic markup automatically.
+
+See sample: `grid-data-table-heuristic.good.al`.