The current layout system uses a complex bidirectional atom architecture
that forces every layout change to round-trip through the backend
WaveObject, even though **the backend never reads this data** - it only
queues actions via `PendingBackendActions`. By switching to a "write
cache" pattern where local atoms are the source of truth and backend
writes are fire-and-forget, we can eliminate ~70% of the complexity
while maintaining full persistence.
----
Every layout change (split, close, focus, magnify) currently follows
this flow:
```
User action
↓
treeReducer() mutates layoutState
↓
layoutState.generation++ ← Only purpose: trigger the write
↓
Bidirectional atom setter (checks generation)
↓
Write to WaveObject {rootnode, focusednodeid, magnifiednodeid}
↓
WaveObject update notification
↓
Bidirectional atom getter runs
↓
ALL dependent atoms recalculate (every isFocused, etc.)
↓
React re-renders with updated state
```
---
## Proposed "Write Cache" Architecture
### Core Concept
```
User action
↓
Update LOCAL atom (immediate, synchronous)
↓
React re-renders (single tick, all atoms see new state)
↓
[async, fire-and-forget] Persist to WaveObject
```
### Key Principles
1. **Local atoms are source of truth** during runtime
2. **WaveObject is persistence layer** only (read on init, write async)
3. **Backend actions still work** via `PendingBackendActions`
4. **No generation tracking needed** (no need to trigger writes)
Moves the wlayout package contents to wcore to prevent import cycles.
Moves the layout calls to other wcore functions instead of being handled
by the services. Removes redundant CreateTab in EnsureInitialData and
adds a isInitialLaunch flag to the CreateTab and CreateWorkspace
functions to ensure that the initial tab is pinned and does not have the
initial tab layout (since the starter layout gets applied later)
