docs: reflect cubecli as standalone crate in README + integration docs

The  binary was extracted to  in a prior session; the
docs still referenced  as its home.

Co-Authored-By: Hermes Agent (upstage/solar-pro4:free)

STARTUP-README.md

@@ -47,7 +47,7 @@ is real. Each must be reproduced live, not asserted.
 3. **Phase 3 syscall surface** — "open by CZYX + flags": a record addressable
    directly by coordinate, not path. **SHIPPED 2026-08-13**:
    (a) `cube open <path> <K.Z.Y.X> <tf>` and `cube seal ...` are first-class CLI
-   commands in `cubesys/src/bin/cube.rs` (reachable in-process + over the durable
+   commands in `cubecli/src/main.rs` (reachable in-process + over the durable
    daemon). Verified: dispatch reaches the crypto/run layer.
    (b) **`.czyx.C.Z.Y.X` FUSE magic-prefix (2026-08-13)** — `cubefs/src/path.rs`
    `parse_dot_czyx` + `cubefs/src/fuse.rs::lookup` intercept: a path component

cubesys/docs/integration.md

@@ -76,9 +76,11 @@ the spec never defined.
 ## Binaries
 
 * `cube-demo` — self-contained tour (write two linked cells, run; seal a
-  record, reopen + run). Prints evidence at each step.
+  record, reopen + run). Prints evidence at each step. (in `cubesys`)
 * `cube` — CLI: `write`, `run`, `ls`, `stat`, `seal`, `open` over one store,
   interactively (`repl`), from a file (`script`), or as the demo (`demo`).
+  Now a standalone crate (`cubecli/`); identical behavior to the former
+  `cubesys/src/bin/cube.rs`.
 * `cube-server` — long-lived daemon: holds ONE `CubeStore` for its whole
   lifetime and serves the same command language over a Unix-domain socket.
   Snapshots the store to a JSON file on every request so the cube survives