docs: add total_videos and tags_with_videos to content/slack endpoint (#82)

Add aggregate video statistics to measure tag-to-video conversion,
mirroring the coding/slack endpoint's PR stats pattern.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: sweetmantech

api-reference/openapi.json

@@ -4300,7 +4300,7 @@
     },
     "/api/admins/content/slack": {
       "get": {
-        "description": "Returns a list of Slack mentions of the Recoup Content Agent bot, pulled directly from the Slack API as the source of truth. Each entry includes the tagger's information, the prompt they sent, the timestamp, the channel, and any video link responses. Supports optional time-period filtering. Requires the authenticated account to be a Recoup admin. Authentication via x-api-key or Authorization Bearer token.",
+        "description": "Returns a list of Slack mentions of the Recoup Content Agent bot, pulled directly from the Slack API as the source of truth. Each entry includes the tagger's information, the prompt they sent, the timestamp, the channel, and any video link responses. Also returns aggregate video statistics for measuring tag-to-video conversion. Supports optional time-period filtering. Requires the authenticated account to be a Recoup admin. Authentication via x-api-key or Authorization Bearer token.",
         "parameters": [
           {
             "name": "period",
@@ -4325,7 +4325,7 @@
               "application/json": {
                 "schema": {
                   "type": "object",
-                  "required": ["status", "total", "tags"],
+                  "required": ["status", "total", "total_videos", "tags_with_videos", "tags"],
                   "properties": {
                     "status": {
                       "type": "string",
@@ -4337,6 +4337,16 @@
                       "description": "Total number of times the Content Agent was tagged in the requested period",
                       "example": 18
                     },
+                    "total_videos": {
+                      "type": "integer",
+                      "description": "Total number of videos generated by the Content Agent across all tags in the requested period",
+                      "example": 12
+                    },
+                    "tags_with_videos": {
+                      "type": "integer",
+                      "description": "Number of tags that resulted in at least one video being generated",
+                      "example": 10
+                    },
                     "tags": {
                       "type": "array",
                       "description": "List of Slack tag events",