Add RFC: Make audio monitoring a output plugin

text/0066-audio-monitoring-output.md

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+- Start Date: 2026-04-08
+- RFC PR: #66
+
+# Summary
+
+Move audio monitoring out of libobs and make it an output plugin.
+
+# Motivation
+
+Currently, when a source is being monitored, a new audio monitor is created for each source. The goal here is to have
+a single mix where all of the sources are output to, thus avoiding sync issues when having multiple sources being
+monitored.
+
+# Detailed design
+
+- This would be an raw audio output
+- Each output can have its own mix, this is set by obs_output_set_mixers()
+- The mix would be hidden from the UI and other outputs
+- When a user selects a source to be monitored, the source mixer is set by obs_source_set_mixers()
+
+# Other conderations
+
+- In the future we could have multiple audio monitoring busses, so creating a new bus would be as simple as creating a
+new output and setting a mixer for it.
+
+# How We Teach This
+
+Nothing would change in the UI.
+
+# Alternatives
+
+Changing libobs to have audio tracks, like we currently have with video tracks. This is kinda redudant, since we have
+audio mixes already.