feat: add getDocumentBytes endpoint for OCR + SignatureRequest context

- New POST /api/v1/SmartAssistant/action/getDocumentBytes returns
  {success, fileName, mimeType, sizeBytes, base64} for use by
  shira-hermes Claude Vision OCR fallback.
- DocumentAnalyzer: new getDocumentBytes() method + guessMimeType helper.
- CaseContextBuilder: expose signatureRequests in case context (for
  DigitalSignature integration — gracefully empty if entity absent).
- README: sync version badge.
- Version bump 2.7.3 → 2.8.0 (new public endpoint).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.taskmaster/tasks/tasks.json

@@ -2,21 +2,38 @@
   "master": {
     "tasks": [
       {
-        "id": 1,
+        "id": "1",
         "title": "fix: broaden task detection to include Contact-linked tasks",
         "description": "AlertCalculator, CaseContextBuilder, and OfficeContextBuilder only queried tasks with parentType='Case', missing tasks linked to case contacts (parentType='Contact'). This caused false 'no preparation task' alerts in Shira's daily standup.",
-        "status": "in-progress",
+        "status": "done",
         "priority": "high",
         "dependencies": [],
         "details": "Root cause confirmed via production API: preparation tasks had parentType='Contact' because Shira created them linked to the contact entity. Fix broadens all task queries to include both Case and Contact parent types, plus NhActivity-linked tasks.",
         "testStrategy": "Deploy to staging, trigger standup for a case with Contact-linked tasks, verify no false alert.",
-        "subtasks": []
+        "subtasks": [],
+        "updatedAt": "2026-04-14T06:08:19.494Z"
+      },
+      {
+        "id": "2",
+        "title": "Network-storage diagnostics + folder discovery",
+        "description": "Expose diagnostics when a case folder can't be listed and add endpoints (findCaseFolder, setCaseFolderPath) so Shira can locate and persist the correct network-storage path.",
+        "details": "",
+        "testStrategy": "",
+        "status": "in-progress",
+        "dependencies": [],
+        "priority": "medium",
+        "subtasks": [],
+        "updatedAt": "2026-04-19T06:11:17.422Z"
       }
     ],
     "metadata": {
-      "created": "2026-04-14T06:05:06.042Z",
-      "updated": "2026-04-14T09:15:00.000Z",
-      "description": "Tasks for master context"
+      "version": "1.0.0",
+      "lastModified": "2026-04-19T06:11:17.423Z",
+      "taskCount": 2,
+      "completedCount": 1,
+      "tags": [
+        "master"
+      ]
     }
   }
-}
+}