Update docs build script and README for current workflow

Make -W (warnings as errors) opt-in via --strict flag instead of
default, and update README to reflect uv-based workflow and current
directory structure.

docs/api/build-docs.sh

@@ -1,5 +1,13 @@
 #!/bin/bash
 
+# Usage: ./build-docs.sh [--strict]
+#   --strict: Treat warnings as errors (default: warnings only)
+
+SPHINX_OPTS=""
+if [ "$1" = "--strict" ]; then
+    SPHINX_OPTS="-W --keep-going"
+fi
+
 # Build docs using uv
 echo "Installing dependencies with uv..."
 uv sync --group docs --all-extras --no-extra gstreamer --no-extra local_smart_turn --no-extra moondream --no-extra mlx-whisper
@@ -14,8 +22,7 @@ fi
 rm -rf _build
 
 echo "Building documentation..."
-# Build docs matching ReadTheDocs configuration
-uv run sphinx-build -b html -d _build/doctrees . _build/html -W --keep-going
+uv run sphinx-build -b html -d _build/doctrees . _build/html $SPHINX_OPTS
 
 if [ $? -eq 0 ]; then
     echo "Documentation built successfully!"