feat: Add profile picture uploads, Redis escrow locking, and fix Socket.io and ETA edge cases

.env.example

@@ -83,3 +83,48 @@ SOROBAN_RPC_RETRY_MAX_MS=8000
 # Maximum times to rebuild and resubmit a transaction after a tx_bad_seq error.
 # Each attempt re-fetches the account sequence number before rebuilding.
 STELLAR_BAD_SEQ_MAX_RETRIES=3
+
+# ─── Redis / Distributed Locking ───────────────────────────────────────────────
+# Redis connection URL for distributed locking (Redlock).
+# REDIS_URL=redis://localhost:6379
+
+# Lock TTL in milliseconds for escrow release operations. Default: 10000
+REDIS_LOCK_TTL_MS=10000
+
+# Maximum retry attempts for acquiring a distributed lock. Default: 3
+REDIS_LOCK_RETRY_COUNT=3
+
+# Delay between lock retry attempts in milliseconds. Default: 200
+REDIS_LOCK_RETRY_DELAY_MS=200
+
+# ─── Socket.io Location Updates ────────────────────────────────────────────────
+# TTL (seconds) for location update deduplication keys in Redis. Default: 60
+LOCATION_DEDUP_TTL_SECONDS=60
+
+# Maximum age (milliseconds) for a location update to be considered valid. Default: 300000 (5 minutes)
+LOCATION_MAX_AGE_MS=300000
+
+# Maximum future timestamp tolerance (milliseconds) for location updates. Default: 30000 (30 seconds)
+LOCATION_MAX_FUTURE_MS=30000
+
+# Socket.io ping timeout in milliseconds. Default: 20000
+SOCKET_PING_TIMEOUT_MS=20000
+
+# Socket.io ping interval in milliseconds. Default: 25000
+SOCKET_PING_INTERVAL_MS=25000
+
+# Maximum consecutive missed pongs before disconnecting. Default: 2
+SOCKET_MAX_MISSED_PONGS=2
+
+# ─── Profile Picture Upload ────────────────────────────────────────────────────
+# Maximum file size for profile pictures in MB. Default: 5
+PROFILE_PICTURE_MAX_SIZE_MB=5
+
+# Target width for resized profile pictures in pixels. Default: 500
+PROFILE_PICTURE_WIDTH=500
+
+# Target height for resized profile pictures in pixels. Default: 500
+PROFILE_PICTURE_HEIGHT=500
+
+# JPEG quality for compressed profile pictures (0-100). Default: 85
+PROFILE_PICTURE_QUALITY=85