feat: add Opus 32k/48k/64k studio quality tiers

Adds three new codec IDs (Opus32k=6, Opus48k=7, Opus64k=8) and
corresponding STUDIO_32K, STUDIO_48K, STUDIO_64K quality profiles.
All use 20ms frames with minimal FEC (10%) for maximum quality on
good networks.

Updated across: wire protocol (codec_id.rs), encoder/decoder
(opus_enc/dec.rs), adaptive codec switch (call.rs), CLI
(--profile studio-64k), desktop engine + UI slider (8 quality
levels from Studio 64k green to Codec2 1.2k red).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

crates/wzp-client/src/call.rs

@@ -532,6 +532,9 @@ impl CallDecoder {
                 frames_per_block: 5,
             },
             CodecId::Opus6k => QualityProfile::DEGRADED,
+            CodecId::Opus32k => QualityProfile::STUDIO_32K,
+            CodecId::Opus48k => QualityProfile::STUDIO_48K,
+            CodecId::Opus64k => QualityProfile::STUDIO_64K,
             CodecId::Codec2_3200 => QualityProfile {
                 codec: CodecId::Codec2_3200,
                 fec_ratio: 0.5,