chore: release v0.54.0

[grhohertz]

chore: release v0.54.0

Version bump + CHANGELOG section for the two features that landed on main past v0.53.4.
0.53.4 -> 0.54.0 — two backward-compatible features, so MINOR per semver.

What's shipping

• PR feat(security): Gate enum + wire egress/sensitive-path hooks + refusal telemetry [TASK-943 / SEC-2.1 / F-01] #936 — Gate enum + wired egress/sensitive-path hooks + refusal telemetry (TASK-943 / SEC-2.1 / F-01).
  The tool gate was a bool: it could say ask or don't ask, never no, so refusals lived as
  out-of-band bail!s beside the gate at each call site. Gate { Allow, Confirm, Refuse } is computed
  once in exec_gate(), which is what lets the egress (PR [SEC-2.2 / F-04] TASK-944: classify network egress in the tool gate #932) and sensitive-path (PR TASK-945: sensitive-path denylist gated in every mode [SEC-2.3 / F-09] #934)
  classifiers stop being return false stubs. Writes whose content executes later
  (.git/hooks/**, .github/workflows/**, .git/config) are refused ahead of every grant;
  the glued env --split-string= / -Ssh bypass is closed; the brittle include_str!-grep
  exhaustiveness test is replaced by #[deny(clippy::wildcard_enum_match_arm)]; and every
  refuse/confirm writes a tool_telemetry row (gate-refuse / gate-confirm) with the rule
  that fired and a bounded bin[:subcommand] — no argv. Deny-by-default Mode::Unattended
  is not in this release (ISS-410409), so no existing mode's effective behaviour changes.

• PR feat(terminal): pin the input line to a fixed footer row in every state #952 — the input line is pinned to a fixed footer row (H-2) in every shell state.
  The one target the operator aims their hands at no longer moves with the transcript.

PR #951 (docs(changelog)) is docs-only and needs no entry of its own.

Release gates (run on a clean checkout of origin/main @ 03be66b)

Gate	Result
cargo fmt --all -- --check	✅ pass
cargo clippy --all-targets --all-features -- -D warnings	✅ pass (0 warnings)
cargo test --workspace	✅ pass
cargo build --release	✅ pass
git tag -l v0.54.0	✅ empty — tag free
Lockfile	✅ only the aish version line changed; no dependency churn

After merge

Tag v0.54.0 on the merge commit and push it — release-production.yml verifies the tag
against Cargo.toml and publishes the release with binary assets. The release is not
to be created by hand (that is what burned v0.48.0 and v0.52.0).

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