feat(#374): add telemetry config to docker-compose and .env

- Add MOSAIC_TELEMETRY_* variables to .env.example with descriptions
- Pass telemetry env vars to api service in production compose
- Pass telemetry env vars to coordinator service in dev and swarm composes
- Swarm composes default to production URL (https://tel-api.mosaicstack.dev)
- Dev compose includes commented-out telemetry-api service placeholder
- All compose files default MOSAIC_TELEMETRY_ENABLED to false for safety

Refs #374

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

docker-compose.swarm.portainer.yml

@@ -255,6 +255,12 @@ services:
       COORDINATOR_POLL_INTERVAL: ${COORDINATOR_POLL_INTERVAL:-5.0}
       COORDINATOR_MAX_CONCURRENT_AGENTS: ${COORDINATOR_MAX_CONCURRENT_AGENTS:-10}
       COORDINATOR_ENABLED: ${COORDINATOR_ENABLED:-true}
+      # Telemetry (task completion tracking & predictions)
+      MOSAIC_TELEMETRY_ENABLED: ${MOSAIC_TELEMETRY_ENABLED:-false}
+      MOSAIC_TELEMETRY_SERVER_URL: ${MOSAIC_TELEMETRY_SERVER_URL:-https://tel-api.mosaicstack.dev}
+      MOSAIC_TELEMETRY_API_KEY: ${MOSAIC_TELEMETRY_API_KEY:-}
+      MOSAIC_TELEMETRY_INSTANCE_ID: ${MOSAIC_TELEMETRY_INSTANCE_ID:-}
+      MOSAIC_TELEMETRY_DRY_RUN: ${MOSAIC_TELEMETRY_DRY_RUN:-false}
     healthcheck:
       test:
         [
@@ -295,6 +301,12 @@ services:
       OLLAMA_ENDPOINT: ${OLLAMA_ENDPOINT:-http://ollama:11434}
       OPENBAO_ADDR: ${OPENBAO_ADDR:-http://openbao:8200}
       ENCRYPTION_KEY: ${ENCRYPTION_KEY}
+      # Telemetry (task completion tracking & predictions)
+      MOSAIC_TELEMETRY_ENABLED: ${MOSAIC_TELEMETRY_ENABLED:-false}
+      MOSAIC_TELEMETRY_SERVER_URL: ${MOSAIC_TELEMETRY_SERVER_URL:-https://tel-api.mosaicstack.dev}
+      MOSAIC_TELEMETRY_API_KEY: ${MOSAIC_TELEMETRY_API_KEY:-}
+      MOSAIC_TELEMETRY_INSTANCE_ID: ${MOSAIC_TELEMETRY_INSTANCE_ID:-}
+      MOSAIC_TELEMETRY_DRY_RUN: ${MOSAIC_TELEMETRY_DRY_RUN:-false}
     healthcheck:
       test:
         [