docs: state current behaviour, drop remaining change-log wording

Refs #3902

docs/agent-lifecycle/persistence.md

@@ -123,8 +123,7 @@ small and carry the semantic per-turn history the operator scrolls
 back through when debugging a regression. Age-only within the
 `stream` kind — no row cap — so a chatty turn doesn't lose its stream
 history sooner than a quiet one. The trade-off (accepted): a
-misbehaving harness could now skip its own cleanup, which the old
-host-side sweep was meant to prevent — but a compromised harness is
+misbehaving harness can skip its own cleanup — but a compromised harness is
 already inside the container trust boundary
 ([`docs/trust-boundary/security.md`](../trust-boundary/security.md)), and these are ephemeral local
 artifacts, so cleaning them up where they live is the honest fix.
@@ -536,12 +535,11 @@ container lifetime:
    recursively so the agent user can read/write it. Wildcard
    matches the single agent that container sees; `-h` skips
    symlinks the agent might have planted.
-4. **Chown the `~/.claude/` bind-mount** recursively. Legacy
-   `claude` wrote `.credentials.json` 0600 root:root; the
-   current harness reads `~/.claude/` as the agent user to decide
-   Online vs NeedsLogin in `login::has_session`. Without the
-   chown the existing credentials get silently treated as "no
-   session" and the operator re-prompts every boot.
+4. **Chown the `~/.claude/` bind-mount** recursively. The harness reads
+   `~/.claude/` as the agent user to decide Online vs NeedsLogin in
+   `login::has_session`. Without the chown, credentials owned by
+   another uid get silently treated as "no session" and the operator
+   re-prompts every boot.
 5. **Hand the socket dir `/run/hive-agent/<name>` to the agent
    user**, `0751`, not recursive. hive-priv creates it `0751 root`
    on the host before every start; the harness binds its sockets