feat(#52): Add Daily Balance mode to ledger Statistics view

docs/mammon-api.yml

@@ -1037,6 +1037,36 @@ paths:
                 $ref: "#/components/schemas/BalanceResponse"
         "404":
           description: No ledger with this id
+  /ledgers/{ledgerId}/balance/daily-valuation:
+    get:
+      tags:
+      - ledger
+      summary: Get the daily mark-to-market valuation series of a ledger's held balance
+        (items and ISK)
+      operationId: dailyValuationForLedger
+      parameters:
+      - name: ledgerId
+        in: path
+        description: Id of the ledger
+        required: true
+        schema:
+          type: string
+          format: uuid
+      responses:
+        "200":
+          description: "Daily average/highest/lowest valuation for the ledger, ascending\
+            \ by date. For a combined ledger, this is the per-date sum of its covered\
+            \ main ledgers' valuations."
+          content:
+            '*/*':
+              schema:
+                type: array
+                items:
+                  $ref: "#/components/schemas/DailyBalanceResponse"
+        "400":
+          description: The ledger is the system ledger
+        "404":
+          description: No ledger with this id
   /corporations:
     get:
       tags:
@@ -2260,6 +2290,36 @@ components:
       required:
       - quantity
       - typeId
+    DailyBalanceResponse:
+      type: object
+      description: "Mark-to-market value of a ledger's held balance (items and ISK)\
+        \ for a single day: average, highest and lowest."
+      properties:
+        date:
+          type: string
+          format: date
+          description: The UTC (EVE) day this valuation is for.
+          example: 2026-06-22
+        averageValue:
+          type: number
+          description: ISK balance plus held item balance valued at that day's average
+            price.
+          example: 1.5E8
+        highestValue:
+          type: number
+          description: ISK balance plus held item balance valued at that day's highest
+            price.
+          example: 1.6E8
+        lowestValue:
+          type: number
+          description: ISK balance plus held item balance valued at that day's lowest
+            price.
+          example: 1.4E8
+      required:
+      - averageValue
+      - date
+      - highestValue
+      - lowestValue
     CorporationResponse:
       type: object
       description: An EVE Online corporation.