feat(telemetry): add CI event tracking for binary downloads and repo clones (#331)

Add a shared shell helper (scripts/ci/track-event.sh) that sends PostHog
events for tracking internal formae binary downloads and repo clones.
Gated on POSTHOG_API_KEY env var — silently no-ops when unset.

Wire it into the Makefile fetch-external-plugins target to track plugin
repo clones.

Author: JeroenSoeters

Makefile

@@ -59,6 +59,7 @@ fetch-external-plugins:
 		else \
 			echo "Cloning $$name..."; \
 			git clone --depth 1 $$repo "$(PLUGINS_CACHE)/$$name"; \
+			. ./scripts/ci/track-event.sh && formae_track_event "ci_repo_clone" "cloned_repo=$$name"; \
 		fi \
 	done
 	@if [ -n "$(AZURE_PLUGIN_REF)" ]; then \

scripts/ci/track-event.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+# © 2025 Platform Engineering Labs Inc.
+#
+# SPDX-License-Identifier: FSL-1.1-ALv2
+#
+# Sends telemetry events to PostHog for tracking CI/dev binary downloads and repo clones.
+# Gated on POSTHOG_API_KEY — if unset, silently does nothing.
+# Usage: source this file, then call formae_track_event "event_name" "key=value" ...
+
+formae_track_event() {
+  local api_key="${POSTHOG_API_KEY:-}"
+  if [[ -z "$api_key" ]]; then return; fi
+
+  local event="$1"; shift
+  local repo
+  repo=$(basename "$(git remote get-url origin 2>/dev/null)" .git 2>/dev/null || echo "unknown")
+
+  local payload
+  payload=$(jq -n \
+    --arg api_key "$api_key" \
+    --arg event "$event" \
+    --arg repo "$repo" \
+    --arg ts "$(date -u +%Y-%m-%dT%H:%M:%SZ)" \
+    --arg run_id "${GITHUB_RUN_ID:-}" \
+    '{
+      api_key: $api_key,
+      distinct_id: "formae-ci",
+      event: $event,
+      timestamp: $ts,
+      properties: {
+        "$process_person_profile": false,
+        repo: $repo,
+        ci_run_id: $run_id
+      }
+    }')
+
+  for kv in "$@"; do
+    local key="${kv%%=*}" val="${kv#*=}"
+    payload=$(echo "$payload" | jq --arg k "$key" --arg v "$val" '.properties[$k] = $v')
+  done
+
+  curl -sf -o /dev/null https://us.i.posthog.com/capture/ \
+    -H "Content-Type: application/json" \
+    -d "$payload" || echo "[telemetry] event send failed (non-critical)" >&2 &
+}