chore(bruno): mark environment IDs as secrets to prevent cross-machine syncing

Remove hardcoded values for database/environment IDs (media_item_id,
library IDs, collection_id, user_id, etc.) and mark them as secret so
that changing them per machine won't keep syncing to git.

bruno/environments/Bookhoard.yml

@@ -2,20 +2,20 @@ name: Bookhoard
 variables:
   - name: base_url
     value: http://localhost:8765
-  - name: media_item_id
-    value: 8bd13107-e1e5-4357-b893-bfc77f1e087c
-  - name: fake_book_id
-    value: 123e4567-e89b-12d3-a456-426614174000
-  - name: user_id
-    value: c51118f0-31fc-4c32-827d-517d6599bf21
-  - name: highlight_id
-    value: 660f9501-f29b-51d4-b716-446655440001
-  - name: note_id
-    value: 7710a602-g29b-61d4-c716-446655440002
-  - name: ebook_library_id
-    value: 0df0ea2b-1965-494a-a0a3-cce8536d5f28
-  - name: job_id
-    value: 709e0d8e-b866-496c-b260-a59ab8e2014c
+  - secret: true
+    name: media_item_id
+  - secret: true
+    name: fake_book_id
+  - secret: true
+    name: user_id
+  - secret: true
+    name: highlight_id
+  - secret: true
+    name: note_id
+  - secret: true
+    name: ebook_library_id
+  - secret: true
+    name: job_id
   - name: rating
     value: "5"
   - name: is_visible
@@ -32,11 +32,11 @@ variables:
     name: kobo_device_token
   - secret: true
     name: other_device_id
-  - name: collection_id
-    value: 412c03c3-0843-4bd4-b764-cc9457bb9df2
-  - name: library_folder_id
-    value: da1f9d91-0c4c-40cc-a050-86f795dfc967
-  - name: comic_library_id
-    value: 7b6d0c8c-73dc-4346-804c-5f6e11c3d658
-  - name: manga_library_id
-    value: b134d16d-9668-4867-b50e-8350037f1a4a
+  - secret: true
+    name: collection_id
+  - secret: true
+    name: library_folder_id
+  - secret: true
+    name: comic_library_id
+  - secret: true
+    name: manga_library_id