feat(capability): 转码能力包（vendor 纯 Go AMR-NB 解码器 + 黄金向量逐样本对照 + 8 哨兵 + 注册面）

internal/capability/transcode/amrnb/dsp_const.go

@@ -0,0 +1,54 @@
+package amrnb
+
+// Core AMR-NB signal-processing constants, from opencore-amrnb cnst.h and
+// mode.h. AMR-NB codes 8 kHz speech in 20 ms frames of 160 samples, with an
+// order-10 LP filter and four 40-sample subframes.
+
+const (
+	cL_FRAME     = 160 // frame size (samples)
+	cL_FRAME_BY2 = 80  // frame size / 2
+	cL_SUBFR     = 40  // subframe size
+	cL_CODE      = 40  // codevector length
+	cNB_SUBFR    = 4   // subframes per frame
+	cL_WINDOW    = 240 // LP analysis window size
+	cL_NEXT      = 40  // LP analysis look-ahead
+	cL_TOTAL     = 320 // total speech analysis buffer
+	cM           = 10  // LP filter order
+	cMP1         = 11  // LP filter order + 1
+	cL_INTERPOL  = 11  // interpolation filter length (10+1)
+	cPIT_MIN     = 20  // minimum pitch lag
+	cPIT_MAX     = 143 // maximum pitch lag
+
+	cAMR_NB_PCM_FRAME = 160 // PCM samples produced/consumed per frame
+	cMAX_PRM_SIZE     = 57  // max number of serial parameters (MR122)
+)
+
+// Internal coding-mode enum, matching opencore-amrnb mode.h (enum Mode). These
+// are the DSP-side mode indices; the public Mode type shares the speech values
+// 0..7, with dMRDTX used for SID/comfort-noise handling.
+const (
+	dMR475 = iota
+	dMR515
+	dMR59
+	dMR67
+	dMR74
+	dMR795
+	dMR102
+	dMR122
+	dMRDTX
+	dNMODES
+)
+
+// Receive frame types, matching opencore-amrnb enum RXFrameType. The decoder
+// driver maps RFC 4867 ToC frame types onto these.
+const (
+	cRX_SPEECH_GOOD = iota
+	cRX_SPEECH_DEGRADED
+	cRX_ONSET
+	cRX_SPEECH_BAD
+	cRX_SID_FIRST
+	cRX_SID_UPDATE
+	cRX_SID_BAD
+	cRX_NO_DATA
+	cRX_N_FRAMETYPES
+)