feat(archive): add observer-feed archive as first-class default-on option

desktop/src-tauri/build.rs

@@ -13,6 +13,7 @@ fn main() {
     println!("cargo:rerun-if-env-changed=BUZZ_BUILD_BUZZ_AGENT_MODEL");
     println!("cargo:rerun-if-env-changed=BUZZ_BUILD_AGENT_ENV");
     println!("cargo:rerun-if-env-changed=BUZZ_BUILD_RELAY_RECONNECT_CMD");
+    println!("cargo:rerun-if-env-changed=BUZZ_BUILD_OBSERVER_ARCHIVE_DEFAULT");
     println!("cargo:rustc-check-cfg=cfg(buzz_updater_enabled)");
 
     if let Ok(relay_url) = std::env::var("BUZZ_RELAY_URL") {
@@ -72,6 +73,14 @@ fn main() {
         println!("cargo:rustc-env=BUZZ_DESKTOP_BUILD_RELAY_RECONNECT_CMD={val}");
     }
 
+    // Presence-only flag: when set (any non-empty value), observer-feed archive
+    // defaults to ON for the current identity on first run.  OSS builds leave
+    // this unset → default OFF.  No JSON validation needed — the command only
+    // checks `.is_some()`.
+    if std::env::var("BUZZ_BUILD_OBSERVER_ARCHIVE_DEFAULT").is_ok() {
+        println!("cargo:rustc-env=BUZZ_DESKTOP_BUILD_OBSERVER_ARCHIVE_DEFAULT=1");
+    }
+
     let updater_public_key = std::env::var("BUZZ_UPDATER_PUBLIC_KEY")
         .ok()
         .map(|value| value.trim().to_string())

desktop/src-tauri/src/commands/mod.rs

@@ -33,6 +33,7 @@ mod project_repo_paths;
 mod project_terminal;
 mod relay_members;
 mod relay_reconnect;
+mod observer_archive;
 mod social;
 mod teams;
 mod updater;
@@ -70,6 +71,7 @@ pub use project_git_diff::*;
 pub use project_terminal::*;
 pub use relay_members::*;
 pub use relay_reconnect::*;
+pub use observer_archive::*;
 pub use social::*;
 pub use teams::*;
 pub use updater::*;

desktop/src-tauri/src/commands/observer_archive.rs

@@ -0,0 +1,36 @@
+//! Build-time flag for observer-feed archive default.
+//!
+//! When `BUZZ_BUILD_OBSERVER_ARCHIVE_DEFAULT` is set at build time (internal
+//! builds), `observer_archive_default_enabled()` returns `true` and the
+//! frontend auto-seeds an `owner_p` save subscription for the current identity
+//! on first run.
+//!
+//! OSS builds (env var unset) return `false` — no auto-seeding, user opts in
+//! manually via the Local Archive settings card.
+
+/// Returns `true` when an internal build has observer-feed archive default-on.
+///
+/// The frontend calls this once at startup to decide whether to seed the
+/// `owner_p` save subscription.  The result is stable for the lifetime of the
+/// binary — it is baked at compile time.
+#[tauri::command]
+pub fn observer_archive_default_enabled() -> bool {
+    option_env!("BUZZ_DESKTOP_BUILD_OBSERVER_ARCHIVE_DEFAULT").is_some()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_observer_archive_default_enabled_returns_bool() {
+        // The command must return a plain bool without panicking.
+        // Whether it's true or false depends on the build environment;
+        // what we assert here is just that the return type is correct and
+        // the function is callable.
+        let result = observer_archive_default_enabled();
+        // In a standard OSS/test build (no BUZZ_DESKTOP_BUILD_OBSERVER_ARCHIVE_DEFAULT
+        // baked in), this should be false.
+        assert!(!result, "expected false in OSS/test build");
+    }
+}

desktop/src-tauri/src/lib.rs

@@ -622,6 +622,7 @@ pub fn run() {
             get_agent_memory,
             relay_reconnect_hook,
             relay_reconnect_hook_configured,
+            observer_archive_default_enabled,
             archive::archive_events,
             archive::create_save_subscription,
             archive::list_save_subscriptions,

desktop/src/app/AppShell.tsx

@@ -50,6 +50,7 @@ import {
 } from "@/features/user-status/hooks";
 import { useWorkspaceEmojiLiveUpdates } from "@/features/custom-emoji/hooks";
 import { useArchiveSync } from "@/features/local-archive/archiveSyncManager";
+import { useObserverArchiveSeed } from "@/features/local-archive/useObserverArchiveSeed";
 import { useProfileQuery } from "@/features/profile/hooks";
 import {
   DEFAULT_SETTINGS_SECTION,
@@ -149,6 +150,7 @@ export function AppShell() {
   usePersonaSync(identityQuery.data?.pubkey);
   useAgentsDataRefresh();
   useArchiveSync();
+  useObserverArchiveSeed(identityQuery.data?.pubkey);
   const profileQuery = useProfileQuery();
   const deferredPubkey = startupReady ? identityQuery.data?.pubkey : undefined;
   useRelayAutoHeal();

desktop/src/features/local-archive/observerArchivePreference.ts

@@ -0,0 +1,71 @@
+/**
+ * Persists whether the user has made an explicit choice about the
+ * observer-feed archive default-on feature.
+ *
+ * The key is identity-scoped so toggling off on one identity doesn't suppress
+ * the default-on for another identity.  The value is:
+ *   "1"  → user explicitly enabled (or accepted the default)
+ *   "0"  → user explicitly disabled
+ *   null → no explicit choice yet (default-on seeding may still fire)
+ *
+ * Device-level localStorage — intentionally not reset on workspace switch
+ * (the archive subscription itself is identity-scoped in SQLite; this flag
+ * is just the UI gate that prevents re-seeding after an explicit opt-out).
+ */
+
+const KEY_PREFIX = "buzz:observer-archive-default-seeded";
+
+function storageKey(identityPubkey: string): string {
+  return `${KEY_PREFIX}:${identityPubkey}`;
+}
+
+/**
+ * Returns `true` if the user has already made an explicit choice for this
+ * identity (either opted in or opted out).  When `false`, the seeding path
+ * may fire.
+ */
+export function hasExplicitObserverArchiceChoice(
+  identityPubkey: string,
+): boolean {
+  if (typeof window === "undefined") return true; // SSR/test: treat as set
+  try {
+    return window.localStorage.getItem(storageKey(identityPubkey)) !== null;
+  } catch {
+    return true; // storage error → treat as set, never auto-seed
+  }
+}
+
+/**
+ * Mark that the user has made an explicit choice for this identity.
+ * `enabled` should reflect whether the `owner_p` subscription exists after
+ * the action (true = seeded/enabled, false = opted out).
+ */
+export function setExplicitObserverArchiveChoice(
+  identityPubkey: string,
+  enabled: boolean,
+): void {
+  if (typeof window === "undefined") return;
+  try {
+    window.localStorage.setItem(
+      storageKey(identityPubkey),
+      enabled ? "1" : "0",
+    );
+  } catch {
+    // Best-effort — the seeding guard will re-fire on next startup if storage
+    // is unavailable, but that is safe (create_save_subscription is idempotent).
+  }
+}
+
+/**
+ * Clear the explicit choice for this identity (for testing / reset flows).
+ */
+export function clearExplicitObserverArchiveChoice(
+  identityPubkey: string,
+): void {
+  if (typeof window === "undefined") return;
+  try {
+    window.localStorage.removeItem(storageKey(identityPubkey));
+  } catch {
+    // ignore
+  }
+}