Add Claude Rules for PDF extractors

Issue: portfolio-performance#5560
Signed-off-by: XY <xy>
[updated path to include portfolio; small changes]
Signed-off-by: Andreas Buchen <andreas.buchen@gmail.com>

Author: gamue

.claude/rules/pdfextractors.md

@@ -0,0 +1,67 @@
+---
+paths:
+ - "name.abuchen.portfolio/src/name/abuchen/portfolio/datatransfer/pdf/*"
+ - "name.abuchen.portfolio.tests/src/name/abuchen/portfolio/datatransfer/pdf/**"
+---
+
+PDF importers extract transactions from bank and broker PDF statements. 
+
+- Each bank/broker has its own extractor class inside `name.abuchen.portfolio/src/name/abuchen/datatransfer/pdf/`
+- Tests are located at `name.abuchen.portfolio.tests/src/name/abuchen/datatransfer/pdf/` within a folder for each bank, containing all connected test-exports.
+
+# Implementation
+
+- `AbstractPDFExtractor` is the base class for every pdf-extractor, containing utility methods
+- `ExtractorUtils` offers additional utility methods, if the ones from the base-class aren't enough.
+- Use `TextUtil` when it's required to manipulate text
+- When implementing a new extractor or adding new parsing logic method, check `BaaderBankPDFExtractor` for reference and use the same pattern
+  - Split logic into methods like `addBuySellTransaction()`, `addDividendTransaction()` or `addInterestTransaction()`
+  - When extracting information from pdf-documents, create multiple `section`-Blocks. 
+  - Consistency in coding style between all extractors is more important than nice code.
+  - Add comment-blocks with `@formatter:off` and `@formatter:on` before each section-block showing the format that is handled there.
+
+
+# Testing
+Test methods should be in following structure
+
+```
+@Test
+public void testWertpapierKauf01()
+{
+    var extractor = new ScalableCapitalPDFExtractor(new Client());
+
+    List<Exception> errors = new ArrayList<>();
+
+    var results = extractor.extract(PDFInputFile.loadTestCase(getClass(), "Kauf01.txt"), errors);
+
+    assertThat(errors, empty());
+    assertThat(countSecurities(results), is(1L));
+    assertThat(countBuySell(results), is(1L));
+    assertThat(countAccountTransactions(results), is(0L));
+    assertThat(countAccountTransfers(results), is(0L));
+    assertThat(countItemsWithFailureMessage(results), is(0L));
+    assertThat(countSkippedItems(results), is(0L));
+    assertThat(results.size(), is(2));
+    new AssertImportActions().check(results, "EUR");
+
+    // check security
+    assertThat(results, hasItem(security( //
+                    hasIsin("IE0008T6IUX0"), hasWkn(null), hasTicker(null), //
+                    hasName("Vngrd Fds-ESG Dv.As-Pc Al ETF"), //
+                    hasCurrencyCode("EUR"))));
+
+    // check purchase transaction
+    assertThat(results, hasItem(purchase( //
+                    hasDate("2024-12-12T13:12:51"), hasShares(3.00), //
+                    hasSource("Kauf01.txt"), //
+                    hasNote("Ord.-Nr.: SCALsin78vS5CYz"), //
+                    hasAmount("EUR", 19.49), hasGrossValue("EUR", 18.50), //
+                    hasTaxes("EUR", 0.00), hasFees("EUR", 0.99))));
+
+}
+```
+
+- Each method has a starting `assertThat`-Block checking the counts. All 8 assertions need to be present.
+- Use `//` to enforce line-breaks when checking securities and transactions
+- Include time (hours, minutes, seconds) in `hasDate` when the source document provides it.
+- The `ExtractorMatchers`-class contains test assertion helpers