refactor(voice): extract reusable Pocket primitives + Pocket voice settings (relands #2467 + #3208) (#3910)

Relands **#2467** (extract `buzz-voice` crate) and **#3208** (Pocket
voice settings) onto main, after #3266 and #3180 merged.

## Why a fresh PR
The repo is squash-only with delete-branch-on-merge. Squashing #3266
deleted `jtennant/pocket-tts-2026-04`, which was #2467's base — GitHub
auto-closed #2467 and it cannot be reopened. Squash merges also sever
ancestry, so GitHub's natural merge-base reports phantom conflicts for
the whole remaining stack.

## Content provenance
- Byte-identical to the blessed `jt/buzz-voice-refactor` branch
(`93029c577`, tree `6729e0eff` — reviewed by Dawn (#2467) and Max
(#3208) at exact heads) **except** the three files where #3180 and #3208
genuinely interact.
- Three-file resolution (union of both sides):
- `huddle/mod.rs` — #3180's pipeline re-exports + #3208's
`agent_tts_routing` imports.
- `huddle/state.rs` — `reset_preserving_generation` preserves both
`huddle_generation` (#3180) and `tts_enabled` (#3208); test sets merged
into one `tests` module.
- `desktop/src/testing/e2eBridge.ts` — both switch arms kept; no
duplicate case labels.

## Verification at cf32dacd7
- `cargo test` (desktop/src-tauri, pinned 1.95.0): **2047 + 3 pass / 0
fail** (14 ignored: 8 keychain, 4 real_relay, 2 flag-gated)
- `cargo clippy --all-targets -- -D warnings`: clean; `cargo fmt
--check`: clean
- `cargo check --workspace` (root, includes new `buzz-voice` member):
clean; `cargo test -p buzz-voice`: 5/0
- `pnpm test`: **3885 / 0**; `tsc --noEmit`: clean; lint: clean

The 3180×3208 interaction resolution is getting an independent team
re-review before merge.

Buzz channel: buzz-desktop-voice `fd5fb402-b651-4238-89b1-bb3e2fa4dc96`,
thread `b4798ecc`.

Signed-off-by: npub1qyvc0c5kl4gqv2fd97fsk46tu378sqgy35vc83rvgfwne90sel7s0ed67d <011987e296fd5006292d2f930b574be47c7801048d1983c46c425d3c95f0cffd@buzz.block.builderlab.xyz>
Co-authored-by: npub1qyvc0c5kl4gqv2fd97fsk46tu378sqgy35vc83rvgfwne90sel7s0ed67d <011987e296fd5006292d2f930b574be47c7801048d1983c46c425d3c95f0cffd@buzz.block.builderlab.xyz>

desktop/src/shared/api/readOnlyRelayClient.ts

@@ -12,7 +12,7 @@ import {
   AUTH_TIMEOUT_MS,
   HISTORY_TIMEOUT_MS,
   PUBLISH_TIMEOUT_MS,
-} from "@/shared/api/relayClientSession";
+} from "@/shared/api/relayClientTimings";
 
 type PendingHistory = {
   events: RelayEvent[];

desktop/src/shared/api/relayChannelFilters.test.mjs

@@ -6,6 +6,7 @@ import {
   buildChannelAuxFilter,
   buildChannelReactionAuxFilter,
   buildChannelStructuralAuxFilter,
+  buildHuddleTtsLiveFilter,
 } from "./relayChannelFilters.ts";
 
 const CHANNEL = "36411e44-0e2d-4cfe-bd6e-567eb169db9f";
@@ -14,6 +15,14 @@ const IDS = [
   "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
 ];
 
+test("huddle TTS filter is future-only for both message kinds", () => {
+  assert.deepEqual(buildHuddleTtsLiveFilter(CHANNEL), {
+    kinds: [9, 40002],
+    "#h": [CHANNEL],
+    limit: 0,
+  });
+});
+
 // Regression: reaction (kind:7) and reaction-removal (kind:5) events carry only
 // an `e` tag, no channel `h` tag. An `#h`-scoped aux query never matches them,
 // so removed historical reactions reappear. The aux filters must key on `#e`

desktop/src/shared/api/relayChannelFilters.ts

@@ -6,6 +6,8 @@ import {
   KIND_DELETION,
   KIND_NIP29_DELETE_EVENT,
   KIND_REACTION,
+  KIND_STREAM_MESSAGE,
+  KIND_STREAM_MESSAGE_V2,
   KIND_STREAM_MESSAGE_EDIT,
 } from "@/shared/constants/kinds";
 import type { RelaySubscriptionFilter } from "@/shared/api/relayClientShared";
@@ -40,6 +42,17 @@ export function buildChannelFilter(
   return filter;
 }
 
+/** Strictly live huddle message filter: zero stored rows, future messages only. */
+export function buildHuddleTtsLiveFilter(
+  channelId: string,
+): RelaySubscriptionFilter {
+  return {
+    kinds: [KIND_STREAM_MESSAGE, KIND_STREAM_MESSAGE_V2],
+    "#h": [channelId],
+    limit: 0,
+  };
+}
+
 /**
  * History filter for cold-load and scrollback: message kinds *only*, so the
  * `limit` budget buys visible message depth. Auxiliary events (reactions,

desktop/src/shared/api/relayClientSession.ts

@@ -53,20 +53,19 @@ import {
 } from "@/shared/api/relayReconnectPolicy";
 import { RelayReconnectWaiters } from "@/shared/api/relayReconnectWaiters";
 import { RelayStallWatchdog } from "@/shared/api/relayStallWatchdog";
+import {
+  AUTH_TIMEOUT_MS,
+  BACKOFF_RESET_STABLE_MS,
+  EVENT_BATCH_MS,
+  HISTORY_TIMEOUT_MS,
+  PUBLISH_TIMEOUT_MS,
+  RECONNECT_BASE_DELAY_MS,
+  RECONNECT_MAX_DELAY_MS,
+  STALL_CHECK_INTERVAL_MS,
+  STALL_IDLE_TIMEOUT_MS,
+} from "@/shared/api/relayClientTimings";
 import { closeWebSocket } from "@/shared/api/relayWebSocketClose";
 import { buildThreadReferenceTags } from "@/features/messages/lib/threading";
-const RECONNECT_BASE_DELAY_MS = 1_000,
-  RECONNECT_MAX_DELAY_MS = 30_000,
-  EVENT_BATCH_MS = 16;
-
-export const AUTH_TIMEOUT_MS = 25_000;
-export const HISTORY_TIMEOUT_MS = 25_000;
-export const PUBLISH_TIMEOUT_MS = 25_000;
-
-export const BACKOFF_RESET_STABLE_MS = 60_000;
-
-const STALL_CHECK_INTERVAL_MS = 10_000;
-const STALL_IDLE_TIMEOUT_MS = 60_000;
 
 export class RelayClient {
   private wsId: number | null = null;

desktop/src/shared/api/relayClientTimings.ts

@@ -0,0 +1,20 @@
+export const RECONNECT_BASE_DELAY_MS = 1_000;
+export const RECONNECT_MAX_DELAY_MS = 30_000;
+export const EVENT_BATCH_MS = 16;
+
+/**
+ * Op-level timeouts tolerate degraded networks where TLS handshakes and DNS
+ * resolution can take several seconds.
+ */
+export const AUTH_TIMEOUT_MS = 25_000;
+export const HISTORY_TIMEOUT_MS = 25_000;
+export const PUBLISH_TIMEOUT_MS = 25_000;
+
+/**
+ * A stability-gated reset prevents reconnect flapping from erasing backoff.
+ */
+export const BACKOFF_RESET_STABLE_MS = 60_000;
+
+/** Passive liveness thresholds for the relay heartbeat stream. */
+export const STALL_CHECK_INTERVAL_MS = 10_000;
+export const STALL_IDLE_TIMEOUT_MS = 60_000;

desktop/src/shared/api/relayReconnectReplay.test.mjs

@@ -5,6 +5,7 @@ import {
   buildReconnectReplayFilter,
   replayLiveSubscriptions,
   REPLAY_BATCH_SIZE,
+  shouldPageReconnectReplay,
 } from "./relayReconnectReplay.ts";
 import { buildChannelFilter } from "./relayChannelFilters.ts";
 
@@ -113,6 +114,31 @@ test("reconnect replay caps large steady-state limits", () => {
   });
 });
 
+test("reconnect replay preserves the live-only zero-history contract", () => {
+  const filter = {
+    kinds: [9],
+    "#h": ["channel-1"],
+    limit: 0,
+  };
+
+  assert.deepEqual(replayFilter(filter, 123), {
+    kinds: [9],
+    "#h": ["channel-1"],
+    limit: 0,
+    since: 123,
+  });
+});
+
+test("live-only subscriptions do not page reconnect history", () => {
+  const filter = {
+    kinds: [9],
+    "#h": ["channel-1"],
+    limit: 0,
+  };
+
+  assert.equal(shouldPageReconnectReplay(filter), false);
+});
+
 test("reconnect replay keeps the stricter existing since window", () => {
   const filter = {
     kinds: [9],