Eventra SDK: fixed a browser-only bug that could silently drop…

Fixed

• Eventra SDK: fixed a browser-only bug that could silently drop tracked events without any visible error.
• CLI: feature-usage tracking calls are now detected correctly even when split across multiple files (e.g. a tracking helper defined in one file, used in another) — previously these could be silently missed during a scan.
• CLI: `eventra send` now correctly reports failure to the calling shell (e.g. a CI pipeline) when it can't send events — missing credentials, an unconfigured destination, or a failed request will now fail the build instead of silently succeeding.
• CLI: `eventra watch` now picks up brand-new files as they're created, instead of only re-scanning files that already existed when watch mode started.