fix(install): add --prefer-binary to pip installs to avoid /tmp exhaustion (#272)

timezonefinder (~54 MB) includes large timezone polygon data files that pip
unpacks into /tmp during installation. On Raspberry Pi, the default tmpfs
/tmp size (often ~half of RAM) can be too small, causing the install to fail
with an out-of-space error.

Adding --prefer-binary tells pip to prefer pre-built binary wheels over
source distributions. Since timezonefinder and most other packages publish
wheels on PyPI (and piwheels.org has ARM wheels), this avoids the large
temporary /tmp extraction and speeds up installs generally.

Co-authored-by: Chuck <chuck@example.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

first_time_install.sh

@@ -676,7 +676,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         
         if command -v timeout >/dev/null 2>&1; then
             # Use timeout if available (10 minutes = 600 seconds)
-            if timeout 600 python3 -m pip install --break-system-packages --no-cache-dir --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
+            if timeout 600 python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
                 INSTALL_SUCCESS=true
             else
                 EXIT_CODE=$?
@@ -684,7 +684,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
                     echo "✗ Timeout (10 minutes) installing: $line"
                     echo "  This package may require building from source, which can be slow on Raspberry Pi."
                     echo "  You can try installing it manually later with:"
-                    echo "    python3 -m pip install --break-system-packages --no-cache-dir --verbose '$line'"
+                    echo "    python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose '$line'"
                 else
                     echo "✗ Failed to install: $line (exit code: $EXIT_CODE)"
                 fi
@@ -692,7 +692,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         else
             # No timeout command available, install without timeout
             echo "  Note: timeout command not available, installation may take a while..."
-            if python3 -m pip install --break-system-packages --no-cache-dir --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
+            if python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose "$line" > "$INSTALL_OUTPUT" 2>&1; then
                 INSTALL_SUCCESS=true
             else
                 EXIT_CODE=$?
@@ -744,7 +744,7 @@ if [ -f "$PROJECT_ROOT_DIR/requirements.txt" ]; then
         echo "  1. Ensure you have enough disk space: df -h"
         echo "  2. Check available memory: free -h"
         echo "  3. Try installing failed packages individually with verbose output:"
-        echo "     python3 -m pip install --break-system-packages --no-cache-dir --verbose <package>"
+        echo "     python3 -m pip install --break-system-packages --no-cache-dir --prefer-binary --verbose <package>"
         echo "  4. For packages that build from source (like numpy), consider:"
         echo "     - Installing pre-built wheels: python3 -m pip install --only-binary :all: <package>"
         echo "     - Or installing via apt if available: sudo apt install python3-<package>"
@@ -766,7 +766,7 @@ echo ""
 # Install web interface dependencies
 echo "Installing web interface dependencies..."
 if [ -f "$PROJECT_ROOT_DIR/web_interface/requirements.txt" ]; then
-    if python3 -m pip install --break-system-packages -r "$PROJECT_ROOT_DIR/web_interface/requirements.txt"; then
+    if python3 -m pip install --break-system-packages --prefer-binary -r "$PROJECT_ROOT_DIR/web_interface/requirements.txt"; then
         echo "✓ Web interface dependencies installed"
         # Create marker file to indicate dependencies are installed
         touch "$PROJECT_ROOT_DIR/.web_deps_installed"
@@ -885,7 +885,7 @@ else
     else
         echo "Using pip to install dependencies..."
         if [ -f "$PROJECT_ROOT_DIR/requirements_web_v2.txt" ]; then
-            python3 -m pip install --break-system-packages -r requirements_web_v2.txt
+            python3 -m pip install --break-system-packages --prefer-binary -r requirements_web_v2.txt
         else
             echo "⚠ requirements_web_v2.txt not found; skipping web dependency install"
         fi

scripts/install_dependencies_apt.py

@@ -52,7 +52,7 @@ def install_via_pip(package_name):
     try:
         print(f"Installing {package_name} via pip...")
         subprocess.check_call([
-            sys.executable, '-m', 'pip', 'install', '--break-system-packages', package_name
+            sys.executable, '-m', 'pip', 'install', '--break-system-packages', '--prefer-binary', package_name
         ])
         print(f"Successfully installed {package_name} via pip")
         return True