feat: add TimescaleDB to nix dev shell

- Use postgresql_16.withPackages to include timescaledb extension
- Add shared_preload_libraries to PostgreSQL config
- Enable TimescaleDB for both dev and test databases
- Disable TimescaleDB telemetry in dev

nix/shell.nix

@@ -26,6 +26,9 @@
 }:
 
 let
+  # PostgreSQL with TimescaleDB extension
+  pg = postgresql_16.withPackages (ps: [ ps.timescaledb ]);
+
   # PostgreSQL data directory (local to project)
   pgDataDir = ".nix-postgres";
   pgPort = "5432";
@@ -53,7 +56,7 @@ let
     # Initialize PostgreSQL if needed
     if [ ! -d "${pgDataDir}" ]; then
       echo "📦 Initializing PostgreSQL database..."
-      ${postgresql_16}/bin/initdb -D ${pgDataDir} -U $USER --encoding=UTF8 --locale=en_US.UTF-8
+      ${pg}/bin/initdb -D ${pgDataDir} -U $USER --encoding=UTF8 --locale=en_US.UTF-8
 
       # Configure PostgreSQL
       cat >> ${pgDataDir}/postgresql.conf << EOF
@@ -63,20 +66,23 @@ let
     fsync = off  # Faster for development (DO NOT use in production)
     synchronous_commit = off
     full_page_writes = off
+    # TimescaleDB
+    shared_preload_libraries = 'timescaledb'
+    timescaledb.telemetry_level = off
     EOF
     fi
 
     # Check if PostgreSQL is already running on this port
-    if ${postgresql_16}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
+    if ${pg}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
       echo "✓ PostgreSQL already running on port ${pgPort}"
     else
       # Start PostgreSQL
       echo "🐘 Starting PostgreSQL on port ${pgPort}..."
-      ${postgresql_16}/bin/pg_ctl -D ${pgDataDir} -l ${pgDataDir}/logfile -o "-p ${pgPort}" start
+      ${pg}/bin/pg_ctl -D ${pgDataDir} -l ${pgDataDir}/logfile -o "-p ${pgPort}" start
 
       # Wait for PostgreSQL to be ready
       for i in {1..30}; do
-        if ${postgresql_16}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
+        if ${pg}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
           break
         fi
         if [ $i -eq 30 ]; then
@@ -90,22 +96,24 @@ let
     fi
 
     # Create postgres role if it doesn't exist (needed by some tools)
-    ${postgresql_16}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -tc \
+    ${pg}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -tc \
       "SELECT 1 FROM pg_roles WHERE rolname='postgres'" | grep -q 1 || \
-      ${postgresql_16}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -c \
+      ${pg}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -c \
         "CREATE ROLE postgres WITH SUPERUSER LOGIN;"
 
     # Create development and test databases
     for db in towerops_dev towerops_test; do
-      ${postgresql_16}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -tc \
+      ${pg}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -tc \
         "SELECT 1 FROM pg_database WHERE datname='$db'" | grep -q 1 || \
-        ${postgresql_16}/bin/createdb -h ${pgHost} -p ${pgPort} -U $USER $db
+        ${pg}/bin/createdb -h ${pgHost} -p ${pgPort} -U $USER $db
     done
 
-    # Enable TimescaleDB extension (dev database only, test uses plain PostgreSQL)
-    ${postgresql_16}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d towerops_dev -c \
-      "CREATE EXTENSION IF NOT EXISTS timescaledb CASCADE;" 2>/dev/null || \
-      echo "⚠️  TimescaleDB not available (optional for development)"
+    # Enable TimescaleDB extension for dev and test databases
+    for db in towerops_dev towerops_test; do
+      ${pg}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d $db -c \
+        "CREATE EXTENSION IF NOT EXISTS timescaledb CASCADE;" 2>/dev/null || \
+        echo "⚠️  TimescaleDB not available for $db (optional)"
+    done
 
     echo "✓ PostgreSQL started successfully"
 
@@ -155,7 +163,7 @@ let
 
     # Stop PostgreSQL
     if [ -d "${pgDataDir}" ]; then
-      ${postgresql_16}/bin/pg_ctl -D ${pgDataDir} stop -m fast 2>/dev/null || true
+      ${pg}/bin/pg_ctl -D ${pgDataDir} stop -m fast 2>/dev/null || true
       echo "✓ PostgreSQL stopped"
     fi
 
@@ -211,8 +219,8 @@ mkShell {
     # Elixir/Erlang
     elixir
 
-    # Databases
-    postgresql_16
+    # Databases (PostgreSQL with TimescaleDB)
+    pg
     redis
 
     # SNMP tools