Codex gate: exposing the full multi-line command in the expanded shell card
newly surfaces secrets on non-first lines (the collapsed header only ever showed
line 1). The old redactor masked only password-shaped fields. Broaden it to mask
common secret forms across the WHOLE command: env/colon assignments for
*TOKEN/*API_KEY/*SECRET/*ACCESS_KEY/*PRIVATE_KEY/*CREDENTIAL/*CLIENT_SECRET/
*SESSION_KEY and *AUTH*=, --token/--api-key/--secret style flags,
Authorization: Bearer/Bot/Token headers, and secret-looking URL query params.
Test now drives the REAL redactor (not an identity stub) and asserts non-first-line
secrets are masked while the collapsed header stays first-line.
In the transparent activity stream, a shell tool card's collapsed header
correctly shows only the first line of the command, but the EXPANDED detail
lead (`$ <command>`) reused that same first-line-only value via
_toolTargetLabel, so a multi-line script still rendered as line 1 when expanded.
The full command is available frontend-side; the truncation was purely in the
label derivation.
Adds _toolFullCommandLabel(tc) (full multi-line, redacted, no first-line
collapse) and uses it in _toolDetailLeadText for the shell kind, while the
collapsed header keeps the first-line _toolTargetLabel. Part of #4925.
