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>

fava_client.py

@@ -1,5 +1,5 @@
 """
-Fava API client for Castle.
+Fava API client for Libra.
 
 This module provides an async HTTP client for interacting with Fava's JSON API.
 All accounting logic is delegated to Fava/Beancount.
@@ -46,7 +46,7 @@ class FavaClient:
 
         Args:
             fava_url: Base URL of Fava server (e.g., http://localhost:3333)
-            ledger_slug: URL-safe ledger identifier (e.g., castle-accounting)
+            ledger_slug: URL-safe ledger identifier (e.g., libra-accounting)
             timeout: Request timeout in seconds
         """
         self.fava_url = fava_url.rstrip('/')
@@ -169,7 +169,7 @@ class FavaClient:
 
         Args:
             entry: Beancount entry dict (same format as add_entry)
-            idempotency_key: Unique key for this operation (e.g., "castle-{uuid}" or "ln-{payment_hash}")
+            idempotency_key: Unique key for this operation (e.g., "libra-{uuid}" or "ln-{payment_hash}")
 
         Returns:
             Response from Fava if entry was created, or existing entry data if already exists
@@ -289,18 +289,18 @@ class FavaClient:
 
     async def get_user_balance(self, user_id: str) -> Dict[str, Any]:
         """
-        Get user's balance from castle's perspective.
+        Get user's balance from libra's perspective.
 
         Aggregates:
-        - Liabilities:Payable:User-{user_id} (negative = castle owes user)
-        - Assets:Receivable:User-{user_id} (positive = user owes castle)
+        - Liabilities:Payable:User-{user_id} (negative = libra owes user)
+        - Assets:Receivable:User-{user_id} (positive = user owes libra)
 
         Args:
             user_id: User ID
 
         Returns:
             {
-                "balance": int (sats, positive = user owes castle, negative = castle owes user),
+                "balance": int (sats, positive = user owes libra, negative = libra owes user),
                 "fiat_balances": {"EUR": Decimal("100.50")},
                 "accounts": [list of account dicts with balances]
             }
@@ -676,12 +676,12 @@ class FavaClient:
         Use this for efficient aggregations, filtering, and data retrieval.
 
         ⚠️ LIMITATION: BQL can only query position amounts and transaction-level data.
-        It CANNOT access posting metadata (like 'sats-equivalent'). For Castle's current
+        It CANNOT access posting metadata (like 'sats-equivalent'). For Libra's current
         ledger format where SATS are stored in metadata, manual aggregation is required.
 
         See: docs/BQL-BALANCE-QUERIES.md for detailed analysis and test results.
 
-        FUTURE CONSIDERATION: If Castle's ledger format changes to use SATS as position
+        FUTURE CONSIDERATION: If Libra's ledger format changes to use SATS as position
         amounts (instead of metadata), BQL could provide significant performance benefits.
 
         Args:
@@ -1031,7 +1031,7 @@ class FavaClient:
         Get total expense contributions per user using BQL.
 
         Uses sum(weight) to aggregate all expenses each user has submitted
-        that created liabilities (castle owes user).
+        that created liabilities (libra owes user).
 
         Returns:
             List of user contribution summaries:
@@ -1601,8 +1601,8 @@ class FavaClient:
 
         Args:
             user_id: User ID (first 8 characters used for account matching)
-            entry_type: "expense" (payables - castle owes user) or
-                       "receivable" (user owes castle)
+            entry_type: "expense" (payables - libra owes user) or
+                       "receivable" (user owes libra)
 
         Returns:
             List of unsettled entries with:
@@ -1742,8 +1742,8 @@ class FavaClient:
 
         Args:
             user_id: User ID (first 8 characters used for account matching)
-            entry_type: "expense" (payables - castle owes user) or
-                       "receivable" (user owes castle)
+            entry_type: "expense" (payables - libra owes user) or
+                       "receivable" (user owes libra)
 
         Returns:
             List of unsettled entries with:
@@ -1896,6 +1896,6 @@ def get_fava_client() -> FavaClient:
     if _fava_client is None:
         raise RuntimeError(
             "Fava client not initialized. Call init_fava_client() first. "
-            "Castle requires Fava for all accounting operations."
+            "Libra requires Fava for all accounting operations."
         )
     return _fava_client