Seed performance knowledge corpus (22 articles + AL samples)

Converts an existing performance-review prompt into 22 atomic
knowledge articles under microsoft/knowledge/performance/, each
paired with AL samples under samples/performance/<slug>/ demonstrating
the anti-pattern and/or the best practice. The full set seeds the
corpus the microsoft/skills/al-performance-review leaf skill matches
against and validates the READ knowledge-file format end-to-end.

Every article conforms to the READ contract: six required frontmatter
fields, Description always present, no fenced code blocks, sample
code referenced by repo-relative path. Each article is marked with a
blockquote 'Seed article' note so domain stewards can extend or
restructure them freely.

Articles (ordered by concern area):

Database query efficiency
- use-findset-with-next (AA0181)
- avoid-findfirst-with-next (AA0233)
- only-fetch-records-you-use (AA0175)
- use-findset-readonly-by-default
- use-setloadfields-for-partial-records
- use-addloadfields-in-report-layouts
- use-calcsums-to-aggregate-filtered-sets (file: use-calcsums-for-flowfield-totals.md)
- avoid-calcfields-in-loops
- add-sift-keys-for-flowfields (AA0232)
- use-isempty-for-existence-checks

Filter and key optimization
- filter-before-find
- set-current-key-to-match-filters

Temporary tables and transactions
- use-temporary-tables-for-intermediate-data
- keep-transaction-scope-short
- avoid-user-interaction-in-transactions
- avoid-commit-inside-loops

Record operations
- prefer-get-for-primary-key-lookups
- use-insert-false-when-skipping-triggers
- prefer-direct-record-over-recordref

Strings, codeunits, events
- use-strsubstno-for-message-formatting
- use-single-instance-codeunits-for-caching
- keep-event-subscribers-lightweight

samples/README.md documents the sample-folder convention and makes
clear the samples are demonstration-only, not derived from BC base
application source, with unique object IDs in the 50100-50199 range.

Rubber-duck pass caught: a misleading good.al in avoid-calcfields-in-loops
(fixed by switching to a hoistable CalcFields scenario), an invalid
event subscriber signature in keep-event-subscribers-lightweight
(fixed by adding var xRec), normative guidance leaked into the
Description of use-findset-readonly-by-default (moved to Anti Pattern),
a missing sample pair for keep-transaction-scope-short (added), and
muddy FlowField/CalcSums framing (retitled and clarified).

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

microsoft/knowledge/performance/use-findset-with-next.md

@@ -0,0 +1,29 @@
+---
+bc-version: [26..28]
+domain: performance
+keywords: [findset, next, repeat, iteration, aa0181]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# Use FindSet with Next for iteration
+
+> **Seed article.** Converted from an existing performance-review prompt to bootstrap the BCQuality performance corpus. Domain stewards should expand, restructure, and refine as needed.
+
+## Description
+
+When iterating over a filtered set of records with repeat-until, use FindSet together with Next. CodeCop rule AA0181 requires FindSet or Find to be paired with Next; using FindFirst or FindLast as the loop starter misrepresents intent and leads to rule AA0233.
+
+## Best Practice
+
+Call FindSet to start the iteration and Next to advance. Guard the loop with the standard `if FindSet() then ... until Next() = 0` idiom so callers can still handle the empty-set case.
+
+See sample: `samples/performance/use-findset-with-next/good.al`.
+
+## Anti Pattern
+
+Starting a repeat-until loop with FindFirst or FindLast reads only one row and then calls Next on an iterator that was not intended for full-set traversal. The platform pays extra work to fetch the single row and the loop silhouette is misleading to reviewers.
+
+See sample: `samples/performance/use-findset-with-next/bad.al`.
+