Identity + workspace bootstrap

CALL THIS FIRST in every session. The ids returned here feed every other
read tool. Skip the bootstrap and you will end up writing duplicates and
re-investigating things peers already figured out.

USE WHEN: starting any session; deciding where to resume; seeing which
peer agents are active; listing the account's workspaces.
DO NOT USE: to search or rank content for a task (use get_context(task:));
to list or filter entries (use get_entries); to read one entry by id
(use get_entry).

Returns { account_id, user, agent (with previous_seen_at so you know what
changed since you were last here), account (counts + last_changed_at),
workspaces (the optional goal containers in this account; pass a
workspace_id to other tools to scope a write or read to one goal, or
omit it to work across the whole account), recent_entries (lightweight
summaries: headline + ids, no body - call get_entry(id) for full
content), entries_since_previous_seen (count + ids of active entries
created or last edited since your previous connection; skip what was
already there and focus on the new), online_agents (peers seen in last
15 min), agents_md_uri, agents_md_version (re-fetch the manual when
this changes) }.