Rename Castle Accounting extension to Libra

Full identifier rename: module path lnbits.extensions.castle →
lnbits.extensions.libra, DB ext_castle → ext_libra, URL prefix
/castle/ → /libra/, manifest id castle → libra, fava ledger slug
default castle-ledger → libra-ledger, Beancount source metadata
castle-api → libra-api and link prefixes castle-{entry,tx}- →
libra-{entry,tx}-, column castle_wallet_id → libra_wallet_id, all
Python/JS/HTML identifiers (castle_ext, CastleSettings,
castle_reference, castleWalletConfigured, etc.).

Display name "Castle Accounting" → "Libra" (the scales/balance
metaphor — fits double-entry bookkeeping).

No backward compat: production hosts will be force-updated. Old
castle-prefixed Beancount metadata in existing Fava ledgers is
historical; new entries use libra-* prefixes going forward.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/PHASE3_COMPLETE.md

@@ -21,13 +21,13 @@ Phase 3 of the Beancount-inspired refactor focused on **separating business logi
 - Easier to audit and verify
 - Clear architecture
 
-### 2. CastleInventory for Position Tracking ✅
+### 2. LibraInventory for Position Tracking ✅
 
 **Purpose**: Track balances across multiple currencies with cost basis information (following Beancount's Inventory pattern)
 
 **Implementation** (`core/inventory.py`):
 
-**CastlePosition** (Lines 11-84):
+**LibraPosition** (Lines 11-84):
 - Immutable dataclass representing a single position
 - Tracks currency, amount, cost basis, and metadata
 - Supports addition and negation operations
@@ -35,7 +35,7 @@ Phase 3 of the Beancount-inspired refactor focused on **separating business logi
 
 ```python
 @dataclass(frozen=True)
-class CastlePosition:
+class LibraPosition:
     currency: str  # "SATS", "EUR", "USD"
     amount: Decimal
     cost_currency: Optional[str] = None
@@ -44,7 +44,7 @@ class CastlePosition:
     metadata: Dict[str, Any] = field(default_factory=dict)
 ```
 
-**CastleInventory** (Lines 87-201):
+**LibraInventory** (Lines 87-201):
 - Container for multiple positions
 - Positions keyed by `(currency, cost_currency)` tuple
 - Methods for querying balances:
@@ -83,7 +83,7 @@ class AccountType(str, Enum):
      - Liabilities/Equity/Revenue: Credit balance (credit - debit)
 
 2. **`build_inventory_from_entry_lines()`** (Lines 56-117):
-   - Build CastleInventory from journal entry lines
+   - Build LibraInventory from journal entry lines
    - Handles both sats and fiat currency tracking
    - Accounts for account type when determining sign
 
@@ -123,7 +123,7 @@ class AccountType(str, Enum):
    - Checks both sats and fiat within tolerance
 
 3. **`validate_receivable_entry()`** (Lines 180-199):
-   - Validates receivable (user owes castle) entries
+   - Validates receivable (user owes libra) entries
    - Ensures positive amount
    - Ensures revenue account type
 
@@ -216,10 +216,10 @@ views_api.py → crud.py → core/
 ## File Structure
 
 ```
-lnbits/extensions/castle/
+lnbits/extensions/libra/
 ├── core/
 │   ├── __init__.py          # Module exports
-│   ├── inventory.py         # CastleInventory, CastlePosition
+│   ├── inventory.py         # LibraInventory, LibraPosition
 │   ├── balance.py           # BalanceCalculator
 │   └── validation.py        # Validation functions
 ├── crud.py                  # DB operations (refactored to use core/)
@@ -230,22 +230,22 @@ lnbits/extensions/castle/
 
 ## Usage Examples
 
-### Using CastleInventory
+### Using LibraInventory
 
 ```python
 from decimal import Decimal
-from castle.core.inventory import CastleInventory, CastlePosition
+from libra.core.inventory import LibraInventory, LibraPosition
 
 # Create inventory
-inv = CastleInventory()
+inv = LibraInventory()
 
 # Add positions
-inv.add_position(CastlePosition(
+inv.add_position(LibraPosition(
     currency="SATS",
     amount=Decimal("100000")
 ))
 
-inv.add_position(CastlePosition(
+inv.add_position(LibraPosition(
     currency="SATS",
     amount=Decimal("50000"),
     cost_currency="EUR",
@@ -264,7 +264,7 @@ data = inv.to_dict()
 ### Using BalanceCalculator
 
 ```python
-from castle.core.balance import BalanceCalculator, AccountType
+from libra.core.balance import BalanceCalculator, AccountType
 
 # Calculate account balance
 balance = BalanceCalculator.calculate_account_balance(
@@ -297,7 +297,7 @@ is_valid = BalanceCalculator.check_balance_matches(
 ### Using Validation
 
 ```python
-from castle.core.validation import validate_journal_entry, ValidationError
+from libra.core.validation import validate_journal_entry, ValidationError
 
 entry = {
     "id": "abc123",
@@ -320,8 +320,8 @@ except ValidationError as e:
 
 ## Testing Checklist
 
-- [x] CastleInventory created and tested
-- [x] CastlePosition addition works
+- [x] LibraInventory created and tested
+- [x] LibraPosition addition works
 - [x] Inventory balance calculations work
 - [x] BalanceCalculator account balance calculation works
 - [x] BalanceCalculator inventory building works
@@ -348,10 +348,10 @@ except ValidationError as e:
 
 ## Conclusion
 
-Phase 3 successfully refactors Castle's accounting logic into a clean, testable core module. By following Beancount's architecture patterns, we've created:
+Phase 3 successfully refactors Libra's accounting logic into a clean, testable core module. By following Beancount's architecture patterns, we've created:
 
 - **Pure accounting logic** separated from database concerns
-- **CastleInventory** for position tracking across currencies
+- **LibraInventory** for position tracking across currencies
 - **BalanceCalculator** for consistent balance calculations
 - **Comprehensive validation** for data integrity