Volter Harness browser observer

This package is a reference observer/control client for an existing Volter Harness SDK runtime. It is not an agent harness or coding IDE. It contains no model routing, tools, sandbox, native-session parser, reduction engine, exporter, or independent persistence engine.

The runtime serves the reference page at /observer/. Paste a scoped runtime credential into the password field. The credential stays in memory and is sent only in authorization headers; it is never put in a URL. The default attachment requests only observe. The optional controls checkbox requests interact and approve, but the page still renders each control only when the runtime's public descriptor advertises the matching action.

Library users can import BrowserObserver and BrowserTranscript. BrowserObserver.discover() accepts explicit endpoint/credential pairs and calls only the public frontend.v2.describe method. Attachment, history replay, live streaming, responses, reconnect cursors, and errors all use @volter/supercode-frontend; native session files are never visible to browser code. The projection is intentionally bounded to 500 rendered cells, 64 KiB per cell, 256 characters per title, and 2 KiB for opaque fallback data. When old cells are omitted the observer says so explicitly; the canonical runtime history remains unchanged and authoritative.