TASK-006: Browse trees and source code by ref

Status: planned — depends on TASK-005 Owner: Codex Reviewer: Claude

Outcome

A user can navigate directories and view source files at an explicit branch, tag, or commit without silently changing refs.

Repository, selected ref, and current path remain visible.
Directory navigation is deterministic and safely handles encoded names.
Text files render with bounded memory use and copy support.
Binary, Git LFS, submodule, unsupported encoding, and oversized-file states have explicit fallbacks.
Loading, empty, offline, authentication-expired, not-found, and server-error states are localized and accessible.
Tests cover ref preservation, path navigation, content classification, and size limits.