[irzhywau]

Part of #260. Stacked on #380 (fix/rustls-0.23.46-advisories); merge after #380.

Behavior

• Runtime marks a full guest store with x-elastos-refusal: guest-capacity, so Home tells "full" from "busy" without reading server text.
• A full passkey challenge pool names its kind (sign-up or sign-in) and sends Retry-After until its oldest challenge expires (at most 300 s). The fixed 60 s is removed.
• Home reads Retry-After and the refusal, then shows one plain reason and one next step:
  • Full: "This Home has no space for new accounts right now. Sign in with an existing account, or try again in about 12 hours."
  • Busy sign-up or sign-in: "… is busy right now. Try again in about 4 minutes."
• A refused completion keeps the created passkey, so a retry replays the same completion.
• Home module stamps move to home-update-20261014a.

Limits, owner enrollment policy and completion replay stay unchanged.

Checks

• cargo test -p elastos-identity --lib webauthn: 26 passed
• cargo test -p elastos-server --lib -- auth_gateway:: passkey_limits:: guest_registration: 93 passed
• cargo clippy -p elastos-identity -p elastos-server --all-targets -- -D warnings: clean
• node --test capsules/home/browser/shell-auth.test.mjs: 8 passed
• scripts/home-shell-auth-gate-smoke.mjs: PASS (guest registration off and on)
• scripts/home-owner-enrollment-smoke.mjs fails on develop too: it removes only the first import from shell-auth.js. This PR does not change that.

Installed saturation and recovery proof stays open in #260.

[andersalm]

Review (Codex, checked by OMP) at 1f466fc: request changes, for after 0.8.0.

• P2: the capacity Retry-After comes from the oldest shared challenge expiry (auth_gateway.rs:4519), which tells an unauthenticated caller another caller's timing; use a public wait independent of other callers.
• P2: shell-auth.js:1018 can tell a user to wait 12 hours after a refused completion while the challenge expires in 300 s (webauthn.rs:19); give a working restart path and a test that proves eventual success.
• P3: shell-auth.js:1026 shows 61-90 s as "about a minute"; round up and test the boundaries.