Add sub stream recording with adaptive quality playback (#24009)

* add sub stream recording with adaptive quality playback

Optionally record a second, lower bitrate stream alongside the main
recording stream via a `record_sub` input role and `record.sub` config block, with its own retention windows.
Recordings rows now carry the stream type plus the media details needed to serve both streams from one manifest: video codec, audio presence, audio codec and rate, and a record-time keyframe index.

Playback resolves coverage across both streams and merges them into a single VOD sequence, falling back to a discontinuity manifest with per-clip init segments when the media signatures differ. The player exposes a quality selector, and an auto governor picks the stream from stall time, bandwidth, codec support, and the save-data hint.

* fix tests and i18n

web/public/locales/en/views/settings.json

@@ -398,6 +398,7 @@
         "title": "Stream Roles",
         "detect": "Main feed for object detection.",
         "record": "Saves segments of the video feed based on configuration settings.",
+        "record_sub": "Lower quality recordings for adaptive playback and extended retention (typically the camera sub stream).",
         "audio": "Feed for audio based detection."
       },
       "featuresPopover": {
@@ -1528,6 +1529,7 @@
       "manual": "Manual arguments",
       "inherit": "Inherit from camera setting",
       "none": "None",
+      "sameAsRecord": "Same as record output arguments",
       "useGlobalSetting": "Inherit from global setting",
       "selectPreset": "Select preset",
       "manualPlaceholder": "Enter FFmpeg arguments",
@@ -1648,9 +1650,12 @@
     "inputRoles": {
       "summary": "{{count}} roles selected",
       "empty": "No roles available",
+      "roleInUse": "Already assigned to another stream",
+      "recordSubConflict": "A stream cannot have both record and record_sub roles",
       "options": {
         "detect": "Detect",
         "record": "Record",
+        "record_sub": "Record (Sub Stream)",
         "audio": "Audio"
       }
     },
@@ -1952,7 +1957,8 @@
       "modelSizeLarge": "The 'large' model is optimized for multi-line license plates. The 'small' model provides better performance over 'large' and should be used unless your region uses multi-line plate formats."
     },
     "record": {
-      "noRecordRole": "No streams have the record role defined. Recording will not function."
+      "noRecordRole": "No streams have the record role defined. Recording will not function.",
+      "noRecordSubRole": "No streams have the record_sub role defined. Sub stream recording will not function."
     },
     "birdseye": {
       "objectTrackingDetectDisabled": "Birdseye includes tracked objects, but object detection is disabled for this camera. The camera will not appear in Birdseye."