D-63: the 0700 data root is the trust boundary already (I-1: hidden, not
locked), so the OS keyring added no wall and cost headless servers a D-Bus
session, CI a knob and every OS its own store. The file keeper is the only
store: run/tokens/, 0600, written atomically. The three keyring stores, the
file_keyring knob and their tests are removed; an unreadable token file is an
error, never no token.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HS8WZziDnyxunC23MUxrLp
swaitsandClaude Fable 5.1
d703b68911