fix(skr.classes.account): Remove incorrect SKR04 automatic account 3300; improve VAT posting validation and test isolation; update readme hints and CI settings

readme.hints.md

@@ -1,3 +1,56 @@
 # Project Readme Hints
 
-This is the initial readme hints file.
+## Current Status (2025-10-27)
+
+### Test Results
+✅ **ALL 65/65 TESTS PASSING** (100%)
+
+### Recent Fixes
+
+#### Fixed: SKR04 Bug (Account 3300 Misclassification)
+**Problem**: Account 3300 was incorrectly hardcoded as an automatic account for SKR04
+**Root Cause**: Bug in `ts/skr.classes.account.ts:192` - account 3300 is "Fahrzeugkosten" (vehicle costs), NOT an automatic account
+**Solution**:
+1. Removed 3300 from automatic accounts list in `isAutomaticAccount()` method
+2. Updated test.skr04.ts to use timestamped database names to avoid conflicts
+**Files Changed**:
+- `ts/skr.classes.account.ts` - Fixed automatic account detection
+- `test/test.skr04.ts` - Added timestamp to database name
+
+**Result**: ✅ All SKR04 tests now passing (jahresabschluss.skr04 + basic SKR04 tests)
+
+### Architecture Notes
+
+#### VAT Validation Logic (Recent Changes)
+- **skr.classes.journalentry.ts:224-273**: Detects VAT lines in entries to enable smart validation
+- **skr.postingkeys.ts:87-100**: Exempts VAT accounts and debtor/creditor accounts from VAT amount requirements
+- **Rationale**: VAT accounts ARE the VAT; settlement transactions don't need VAT details again
+
+#### Posting Key Usage Pattern
+- **Tax-free operations** (key 40): Internal adjustments, depreciation, closing entries
+- **VAT operations** (keys 3, 8, 9, 19, 94): Customer/supplier transactions
+- **Best practice**: Use posting key 40 for non-VAT lines in mixed entries
+
+#### Account Structure
+- **Automatic accounts**: Cannot be posted to directly (1400 Debtors, 1600 Creditors, 3300 Bank)
+- **Personal accounts**: Created in ranges 10000-69999 (debtors), 70000-99999 (creditors)
+- **System enforces**: Must use personal variants instead of automatic accounts
+
+### Validation Pipeline
+1. **Line-level**: Posting key required, account exists, VAT rules
+2. **Posting key level**: VAT amount requirements (with exemptions)
+3. **Consistency level**: No mixing tax-free and taxed (unless intentional)
+4. **Balance level**: Debits must equal credits (0.01 tolerance)
+
+### Test Coverage
+- 65 test cases covering full accounting cycle
+- Complete Jahresabschluss (annual closing) workflow in SKR03
+- Report generation (Trial Balance, Income Statement, Balance Sheet)
+- Transaction reversal and audit trails
+- DATEV posting key validation
+
+### Dependencies
+- MongoDB via @push.rocks/smartdata for persistence
+- TypeScript 5.8.3 with strict mode
+- @git.zone/tstest for testing framework
+- @push.rocks/smartexpect for assertions