feat: add abstract local peer communication - #561

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@firmware/host/modules/connectivity/__tests__/local-peer-frame.test.ts`:
- Around line 20-24: Update the hash assertion in the “local peer UTF-8 codec
round-trips ASCII, Japanese, and supplementary characters” test to compare
fnv1a32(value) against a precomputed known FNV-1a expected value, rather than
invoking fnv1a32 on the same input on both sides. Keep the existing UTF-8
round-trip assertion unchanged.

In `@firmware/host/modules/connectivity/__tests__/local-peer-service.test.ts`:
- Around line 6-261: Move the runtime-focused tests in
firmware/host/modules/connectivity/__tests__/local-peer-service.test.ts (lines
6-261), including FakeRadioNetwork, FakeRadio, openPair, and the
LocalPeerService lifecycle/retry cases, into XS-driven Moddable coverage while
preserving their behaviors. Replace the source/manifest rescanning assertions in
firmware/host/modules/connectivity/__tests__/local-peer.architecture.ts (lines
1-35) with runtime checks, or document the architectural rationale with
source-level why-comments instead.

In `@firmware/host/modules/connectivity/__tests__/stored-wifi.test.ts`:
- Around line 121-137: Move the clearStoredWiFiCredentials behavior test from
the Node suite into the XS-driven Moddable harness, preserving its setup and
network-stop assertions. In the migrated test, directly verify that both stored
preference keys, wifi.ssid and wifi.password, are empty after clearing; do not
rely solely on connectStoredWiFi() returning false.

In `@firmware/host/modules/connectivity/esp32/local-peer-radio.c`:
- Around line 144-155: The callbacks around the shown send-status handler and
the callback covering lines 164–207 must synchronize access to gLocalPeerRadio
with localPeerNativeClose. Hold the same close/lookup lock while reading the
global, checking radio->closed, and incrementing useCount, then release it
before posting or other callback work; ensure no radio fields are dereferenced
before the reference is acquired.

In `@firmware/host/modules/connectivity/esp32/local-peer-radio.js`:
- Around line 23-32: Update the construction error path in the local peer radio
initialization to roll back the native radio after nativeConstruct succeeds but
nativeGetID fails. In the catch block surrounding nativeConstruct and
nativeGetID, release or reset the native object and clear the occupied
gLocalPeerRadio state before closing Wi-Fi and rethrowing the original error.

In `@firmware/host/modules/connectivity/local-peer-service.ts`:
- Around line 542-552: In the reliable-message handling flow around `#deliver` and
`#sendAcknowledgement`, queue and complete the acknowledgement before invoking
subscribers via `#deliver`, while preserving duplicate suppression and existing
acknowledgement behavior. Ensure a synchronous close() from a subscriber cannot
interrupt ACK completion, and add a regression test covering close() from the
message handler without causing a sender timeout.

In `@web/preference/index.html`:
- Around line 88-90: Update the catch block handling the save-status failure so
null or undefined rejection values do not cause a second exception when reading
error.message. Safely derive the displayed error detail before calling
setStatus, while preserving the existing message and error status for ordinary
Error objects.

In `@web/web-ui.test.mjs`:
- Around line 41-50: Replace the source-text regex assertions in the preference
test with a runtime interaction test that loads the preference page, stubs
confirmation and client.send, and clicks the wifi-clear-button. Assert the
resulting _batch payload, cleared SSID/password fields, success status, and
recovery of the button’s disabled state; retain only assertions that verify
actual rendered behavior.

---

Nitpick comments:
In `@firmware/host/app/runtime-context.ts`:
- Around line 489-495: Update createConnectivityCapability to preserve all
existing ConnectivityCapability fields: return connectivity directly when
localPeer is absent, and spread ...connectivity when constructing the wrapped
result before overriding localPeer. Keep the current localPeer wrapping behavior
unchanged.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@firmware/scripts/smoke-lin.sh`:
- Around line 74-75: Remove the global set +e before the timeout invocation in
the smoke script. Update the command handling around timeout in the smoke
execution flow to explicitly capture and evaluate its exit status, preserving
the intended timeout behavior without bypassing errexit or configured ERR traps.