Related: #102754 · Stacked on #103359 (memories) — lands last in the batch.

What Problem This Solves

The lobster lives in one sidebar. This PR gives the ecosystem its wild cards: a terminal cousin, a reaction to gateway upgrades, and a voice (strictly opt-in).

Why This Change Was Made

The CLI cousin. On roughly one day in sixteen — picked by a deterministic hash of the calendar date, so every terminal in the house agrees it is lobster day — the interactive openclaw banner gains a tiny ASCII lobster:

  (\/)  (\/)
   \_\  /_/
    ( o.o )
    /|__|\
🦞 OpenClaw 2026.7.1 (3dd771b) — I've survived more breaking changes than your last three relationships.

Two art variants (claws-up, and just eyestalks above the waterline). Guardrails: rich TTYs only, only in random tagline mode (pinned/off modes read as "keep my banner boring" and are respected), and never in CI/VITEST environments — the existing banner tests assert exact bytes and keep passing. The date is injectable through the existing TaglineOptions.now seam, same as holiday taglines.

Moving day. The pet remembers which gateway version it lives with (browser-local). The first page load after the version changes, it arrives carrying a bindle — stick, polka-dot bundle — and its tooltip reads "Pinchy · just moved in" for that load. The very first version sighting only records a baseline; no bindle without a previous home. Wired through app-host (serverVersion ?? hello.server.version) → sidebar → pet, latched once per load so a late-arriving hello still counts. The shed molt shell, the twin, and passers-by never carry it, and the retro grail's mega claw keeps its shoulder (it moves light).

Lobster sounds, opt-in. A new Quick Settings toggle next to Lobster visits, default off, persisting only an explicit opt-in (mirror image of the visits key, which persists only an explicit opt-out). When on: a tiny descending WebAudio blub on pokes, a rising coo on pets — synthesized, ~150ms, quiet (peak gain 0.05). The AudioContext is created inside the pointer gesture (autoplay-policy safe), all audio failures are swallowed, and the context is closed on disconnect.

Docs. /web/lobster learns about petting, cursor-watching, and the sounds toggle, plus new spoiler-light field notes (strangers who do not stop, a visitor that insists it is a lobster, familiarity, what upgrade visitors carry, the terminal cousin, vigil solidarity) and a Lobsterdex-memories line — covering this whole 4-PR batch.

User Impact

Terminal users get a rare surprise that never contaminates scripts, pipes, or CI. Upgrading the gateway earns a small visual acknowledgment. People who want a slightly audible lobster can have one; everyone else hears exactly what they hear today, which is nothing.

Evidence

Moving day
Sounds toggle

Validation (delegated remote box):

• pnpm test src/cli/lobster-art.test.ts src/cli/banner.test.ts ui/src/components/lobster-pet.test.ts ui/src/components/lobster-dex.test.ts ui/src/pages/config/quick.test.ts — 84/84 green (4 + 9 + 71 across the CLI and UI test projects). New coverage: day-hash determinism + rarity band + CI suppression; banner integration (art present on a probed lobster day in rich random mode, absent for plain terminals and pinned modes); bindle on upgrade + baseline-only on first sighting + same-version reloads travel light; sounds silent by default and chirping only when enabled (AudioContext constructor spy).
• pnpm tsgo:core, pnpm tsgo:core:test, pnpm tsgo:test:ui, pnpm --dir ui build.
• Live browser proof against the mock: the mock hello's version flowed app-host → sidebar → pet and recorded itself to storage; with sounds enabled one poke created exactly one AudioContext and started one oscillator (instrumented), startle act fired; banner render above produced with the real emitCliBanner.
• New i18n keys synced across locale bundles.
• Codex autoreview clean.