feat: rewrite setup.sh as menu-driven installer with profile system

Replace the linear setup.sh with an interactive menu-driven installer:
- First-time wizard with OS detection and profile selection
- Install profiles: Core SIGINT, Maritime, Weather, RF Security, Full, Custom
- System health check (tools, SDR devices, ports, permissions, venv, PostgreSQL)
- Automated PostgreSQL setup for ADS-B history (creates DB, user, tables, indexes)
- Environment configurator for interactive INTERCEPT_* variable editing
- Update tools (rebuild source-built binaries)
- Uninstall/cleanup with granular options and double-confirm for destructive ops
- View status table of all tools with installed/missing state
- CLI flags: --non-interactive, --profile=, --health-check, --postgres-setup, --menu
- .env file helpers (read/write) with start.sh auto-sourcing
- Bash 3.2 compatible (no associative arrays) for macOS support

Update all documentation to reflect the new menu system:
- README.md: installation section with profiles, CLI flags, env config, health check
- CLAUDE.md: entry points and local setup commands
- docs/index.html: GitHub Pages install cards with profile mentions
- docs/HARDWARE.md: setup script section with profile table
- docs/TROUBLESHOOTING.md: health check and profile-based install guidance
- docs/DISTRIBUTED_AGENTS.md: controller quick start

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

start.sh

@@ -17,6 +17,14 @@ set -euo pipefail
 
 # ── Resolve Python from venv or system ───────────────────────────────────────
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# ── Load .env if present ──────────────────────────────────────────────────────
+if [[ -f "$SCRIPT_DIR/.env" ]]; then
+    set -a
+    source "$SCRIPT_DIR/.env"
+    set +a
+fi
+
 if [[ -x "$SCRIPT_DIR/venv/bin/python" ]]; then
     PYTHON="$SCRIPT_DIR/venv/bin/python"
 elif [[ -n "${VIRTUAL_ENV:-}" && -x "$VIRTUAL_ENV/bin/python" ]]; then