feat: rewrite stt-module (HTTP variant) in Go

Replace Python streaming STT service with Go for smaller container images.
Local Whisper/ROCm variant (stt_streaming_local.py, Dockerfile.rocm) stays Python.

- AudioBuffer with session state management (listening/responding)
- RMS-based voice activity detection (pure Go, no cgo)
- Interrupt detection during LLM response playback
- JetStream AI_VOICE_STREAM setup
- Session auto-creation and cleanup
- Dockerfile: multi-stage golang:1.25-alpine → scratch
- CI: Gitea Actions with lint/test/release/docker/notify

Dockerfile

@@ -1,14 +1,23 @@
-FROM python:3.12-slim
+# Build stage — Go STT streaming service (HTTP variant)
+FROM golang:1.25-alpine AS builder
 
 WORKDIR /app
 
-# Copy requirements and install dependencies
-COPY requirements.txt .
-RUN pip install --no-cache-dir -r requirements.txt
+RUN apk add --no-cache ca-certificates
 
-# Copy application code
-COPY stt_streaming.py .
-COPY healthcheck.py .
+COPY go.mod go.sum ./
+RUN go mod download
 
-# Run the service
-CMD ["python", "stt_streaming.py"]
+COPY . .
+
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-w -s" -o /stt-module .
+
+# Runtime stage
+FROM scratch
+
+COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+COPY --from=builder /stt-module /stt-module
+
+USER 65534:65534
+
+ENTRYPOINT ["/stt-module"]