ci: build wickra-examples bins instead of removed cargo examples

The Z5 reorganisation moved every runnable example out of the per-crate
examples/ folders and into a dedicated wickra-examples crate at
examples/rust/, with the binaries living under src/bin/<name>.rs. The
old ci.yml Compile-examples step still pointed at the now-deleted
cargo example targets backtest (wickra) and live_binance (wickra-data),
which is why Rust windows-latest failed with 'no example target named
backtest in wickra package' and 'no example target named live_binance
in wickra-data package'.

Replace both calls with a single cargo build -p wickra-examples --bins.
That covers backtest, live_binance, fetch_btcusdt, multi_timeframe,
parallel_assets and streaming in one shot, and the wickra-examples
crate already enables the live-binance feature on its wickra-data dep
so no extra --features flag is needed.

.github/workflows/ci.yml

@@ -48,9 +48,12 @@ jobs:
         run: cargo build -p wickra --benches --verbose
 
       - name: Compile examples
-        run: |
-          cargo build -p wickra --example backtest
-          cargo build -p wickra-data --example live_binance --features live-binance
+        # All runnable examples now live in the dedicated wickra-examples crate
+        # (examples/rust/src/bin/*.rs) which enables the live-binance feature
+        # on its wickra-data dep, so a single --bins build covers backtest,
+        # live_binance, fetch_btcusdt, multi_timeframe, parallel_assets and
+        # streaming.
+        run: cargo build -p wickra-examples --bins
 
   # Verify the crates still build and test on their declared minimum supported
   # Rust version. The workspace pins rust-version = "1.75"; bindings/node needs