bruno: replace Python generator with Go golden-writer in the drift test

The generator moves into the Go toolchain per repo preference:
internal/docs/bruno_gen.go emits the OpenCollection mirrors (same output
contract — gate-verified example-request bodies, env-var params,
device-token headers, login/register/refresh token-capture scripts) and
TestBrunoMirrorsDocs grows a -update flag: verification by default,
regeneration on demand:

  go test ./internal/docs -run TestBrunoMirrorsDocs -update

Generator and checker are now the same code — they cannot drift apart.
scripts/gen_bruno_from_docs.py deleted; opencollection.yml README points
at the go-test command.

Also fixed vs the Python pass: mirror placement follows the docs tree
folder (RelPath), not the area frontmatter (several docs — highlights,
notes, ratings, users, progress — carry a different area); docs blocks
emit the collection's mapping form (content + type), not a bare scalar;
JSON body sanity is checked at generation time.

Idempotent: back-to-back -update runs are byte-identical.
make test green (9 pkgs).

bruno/collections/add_auto_assign_rule.yml

@@ -23,9 +23,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Add Auto-Assign Rule
+docs:
+  content: |-
+    # Add Auto-Assign Rule
 
-  `POST /api/collections/:id/rules` — auth: jwt.
+    `POST /api/collections/:id/rules` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/add_auto_assign_rule.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/add_auto_assign_rule.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/bulk_add_books.yml

@@ -26,9 +26,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Bulk Add Books
+docs:
+  content: |-
+    # Bulk Add Books
 
-  `POST /api/collections/bulk-add-books` — auth: jwt.
+    `POST /api/collections/bulk-add-books` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/bulk_add_books.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/bulk_add_books.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/bulk_assign.yml

@@ -23,9 +23,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Bulk Assign Books
+docs:
+  content: |-
+    # Bulk Assign Books
 
-  `POST /api/collections/:id/books` — auth: jwt.
+    `POST /api/collections/:id/books` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/bulk_assign.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/bulk_assign.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/bulk_remove_books.yml

@@ -22,9 +22,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Bulk Remove Books
+docs:
+  content: |-
+    # Bulk Remove Books
 
-  `POST /api/collections/:id/books/bulk-remove` — auth: jwt.
+    `POST /api/collections/:id/books/bulk-remove` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/bulk_remove_books.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/bulk_remove_books.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/create_collection.yml

@@ -25,9 +25,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Create Collection
+docs:
+  content: |-
+    # Create Collection
 
-  `POST /api/collections` — auth: jwt.
+    `POST /api/collections` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/create_collection.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/create_collection.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/create_shelf_mapping.yml

@@ -5,7 +5,7 @@ info:
 
 http:
   method: POST
-  url: '{{base_url}}/api/devices/{{collection_id}}/collections'
+  url: '{{base_url}}/api/devices/{{device_id}}/collections'
   auth: inherit
   body:
     type: json
@@ -21,9 +21,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Create Shelf Mapping
+docs:
+  content: |-
+    # Create Shelf Mapping
 
-  `POST /api/devices/:id/collections` — auth: jwt.
+    `POST /api/devices/:id/collections` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/create_shelf_mapping.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/create_shelf_mapping.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/delete_collection.yml

@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Delete Collection
+docs:
+  content: |-
+    # Delete Collection
 
-  `DELETE /api/collections/:id` — auth: jwt.
+    `DELETE /api/collections/:id` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/delete_collection.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/delete_collection.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/delete_shelf_mapping.yml

@@ -5,7 +5,7 @@ info:
 
 http:
   method: DELETE
-  url: '{{base_url}}/api/devices/{{collection_id}}/collections/{{collection_id}}'
+  url: '{{base_url}}/api/devices/{{device_id}}/collections/{{collection_id}}'
   auth: inherit
 settings:
   encodeUrl: true
@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Delete Shelf Mapping
+docs:
+  content: |-
+    # Delete Shelf Mapping
 
-  `DELETE /api/devices/:id/collections/:collectionId` — auth: jwt.
+    `DELETE /api/devices/:id/collections/:collectionId` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/delete_shelf_mapping.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/delete_shelf_mapping.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/get_collection.yml

@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Get Collection
+docs:
+  content: |-
+    # Get Collection
 
-  `GET /api/collections/:id` — auth: jwt.
+    `GET /api/collections/:id` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/get_collection.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/get_collection.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/get_collection_books.yml

@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Get Book Collections
+docs:
+  content: |-
+    # Get Book Collections
 
-  `GET /api/collections/:id/books` — auth: jwt.
+    `GET /api/collections/:id/books` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/get_collection_books.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/get_collection_books.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/list_collections.yml

@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # List Collections
+docs:
+  content: |-
+    # List Collections
 
-  `GET /api/collections` — auth: jwt.
+    `GET /api/collections` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/list_collections.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/list_collections.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/preview_collection.yml

@@ -22,9 +22,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Preview Collection
+docs:
+  content: |-
+    # Preview Collection
 
-  `POST /api/collections/preview` — auth: jwt.
+    `POST /api/collections/preview` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/preview_collection.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/preview_collection.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/remove_auto_assign_rule.yml

@@ -13,9 +13,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Remove Auto-Assign Rule
+docs:
+  content: |-
+    # Remove Auto-Assign Rule
 
-  `DELETE /api/collections/:id/rules/:ruleId` — auth: jwt.
+    `DELETE /api/collections/:id/rules/:ruleId` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/remove_auto_assign_rule.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/remove_auto_assign_rule.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/reorder_items.yml

@@ -22,9 +22,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Reorder Collection Items
+docs:
+  content: |-
+    # Reorder Collection Items
 
-  `PUT /api/collections/:id/items/order` — auth: jwt.
+    `PUT /api/collections/:id/items/order` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/reorder_items.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/reorder_items.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/test_rule.yml

@@ -30,9 +30,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Test Rule
+docs:
+  content: |-
+    # Test Rule
 
-  `POST /api/collections/test-rules` — auth: jwt.
+    `POST /api/collections/test-rules` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/test_rule.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/test_rule.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/update_collection.yml

@@ -26,9 +26,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Update Collection
+docs:
+  content: |-
+    # Update Collection
 
-  `PUT /api/collections/:id` — auth: jwt.
+    `PUT /api/collections/:id` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/update_collection.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/update_collection.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown

bruno/collections/update_rule.yml

@@ -19,9 +19,11 @@ settings:
   followRedirects: true
   maxRedirects: 5
 
-docs: |-
-  # Update Collection Rule
+docs:
+  content: |-
+    # Update Collection Rule
 
-  `PUT /api/collections/:id/rules/:ruleId` — auth: jwt.
+    `PUT /api/collections/:id/rules/:ruleId` — auth: jwt.
 
-  Canonical reference: `docs/developer/api/collections/update_rule.md` (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, not this file.
+    Canonical reference: docs/developer/api/collections/update_rule.md (docs site → Developer → API). This request is GENERATED from that doc; edit the doc, then run the drift test with -update.
+  type: text/markdown