feat(diagnostics): funnel events throughout setup with persisted install-id

Shared bash + node emitter in setup/lib/diagnostics.{sh,ts} reads/writes data/install-id so every event from a single install shares one distinct_id — bash-side setup_launched/setup_start, node-side auto_started, per-step started/completed, auth_method_chosen, channel_chosen, first_chat_ready/failed, setup_incomplete, setup_aborted, setup_completed. Opt-out via NANOCLAW_NO_DIAGNOSTICS=1.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nanoclaw.sh

@@ -29,6 +29,14 @@ LOGS_DIR="$PROJECT_ROOT/logs"
 STEPS_DIR="$LOGS_DIR/setup-steps"
 PROGRESS_LOG="$LOGS_DIR/setup.log"
 
+# Diagnostics: persisted install-id + fire-and-forget emit. Sourced early
+# so `setup_launched` covers dropoff before bootstrap even starts.
+# shellcheck source=setup/lib/diagnostics.sh
+source "$PROJECT_ROOT/setup/lib/diagnostics.sh"
+ph_event setup_launched \
+  platform="$(uname -s | tr 'A-Z' 'a-z')" \
+  is_wsl="$([ -f /proc/version ] && grep -qi 'microsoft\|wsl' /proc/version 2>/dev/null && echo true || echo false)"
+
 # ─── log helpers ────────────────────────────────────────────────────────
 
 ts_utc() { date -u +%Y-%m-%dT%H:%M:%SZ; }