Creates a DirectConversationLogIndex using the current environment.
Creates a DirectConversationLogIndex using the current environment.
Reads CLAUDE_CONFIG_DIR from the environment at construction time (eagerly, not deferred). An empty string is treated as unset. No shell ~ expansion is performed on the value. Falls back to os.home / ".claude" when the variable is absent or empty.
Tests that need to mutate the environment after construction should use the two-arg apply(configDirOverride, home) seam instead.