Two independent Svelte 5 effect-loop bugs that triggered the
same 'effect_update_depth_exceeded' guard:
1. PostCard.svelte: the embed-quote-fetch $effect and the
likedBox $effect.pre read a state variable (quotedLoading /
likedBox) and then synchronously wrote to it in the same
effect run. Svelte 5's effect tracker schedules
possible_effect_self_invalidation on the touched state, the
effect re-fires immediately, and the cycle trips the
'flush_count > 1000' guard. With ~30 PostCards mounting on
login the per-card loop compounds into the depth exceeded
error. Wrap the read+write blocks in untrack() so the
hydration flags don't contribute to the effect's dep set;
the outer 'post.embed.uri / post.did / post.rkey' reads
remain tracked so navigation between cards still triggers a
fresh hydrate.
2. App.svelte: the four $effect blocks (home-refresh,
home-poll, profile-refresh, search-debounce) lived and died
together. Even after splitting, Svelte 5 still flagged the
call chain into refreshTimeline / refreshProfile because
their sync prelude writes 'timelineLoading = true' /
'profileLoading = true' while the effect already tracks the
same downstream state via the proxy. Drive everything
imperatively through a single setView(v) function and move
the 5s poll into the session.subscribe callback, which fires
only on actual login/logout transitions. setView is the
single point that flips view AND triggers the right refresh
per destination — NavRail on_select, LoginScreen onLogin,
handleLogout, the 'back to timeline' button, and the tray
navigate-event bridge all route through it now.
Also: NavRail and StatusBar self-style their grid-area in
their own component styles ('grid-area: rail' / 'status') so
App.svelte doesn't need the fragile '$state.s-XXX > nav.rail'
cross-component selector that Svelte 5 was failing to match
in the Tauri webview, leaving rail buttons invisible to clicks.