python: drop the NumPy runtime dependency (zero third-party deps) (#317)

Makes the Python binding truly dependency-free (Task 5b). `pip install wickra` now pulls **zero** third-party packages, and `import wickra` never imports NumPy (verified: `"numpy" not in sys.modules` after a batch call).

## What changed
- **Inputs** accept any sequence or buffer of numbers — `array.array`, `memoryview`, a NumPy `ndarray`, or a plain `list` — via `Vec` extraction (newtypes `Buf1`/`BufI64`). `PyBuffer` is unavailable under `abi3-py39`, and `unsafe_code = forbid` rules out a zero-copy slice, so inputs are copied once (negligible vs. compute).
- **Single-output `batch(...)`** returns a stdlib `array.array('d')` (native buffer protocol → `numpy.asarray` zero-copy).
- **Multi-output `batch(...)`** returns a buffer-protocol `Matrix` preserving `.shape`, integer-row and `[i, j]` access, and `.tolist()`.
- **NumPy** moves to an optional extra (`pip install wickra[numpy]`); it is never required.
- Streaming `update(...)` is unchanged; results are numerically identical.

## Implementation
- Trait `IntoPyData` + a `matrix()`/`f64_array()` helper collapse the ~400 batch call sites; `array.array` is built via `bytemuck` (Zlib/MIT/Apache — `cargo deny check licenses` ok).
- Tests migrated to `array.array`/`Matrix` (1-D `.shape`→`len()`, `.dtype`→`.typecode`; numeric comparisons normalize through a `_to_np` helper). The non-contiguous-input test now asserts acceptance instead of rejection.

## Verification (local)
- `pytest bindings/python/tests` — **1991 passed**.
- `cargo fmt --all`, `cargo clippy --workspace --all-targets --all-features -- -D warnings`, `cargo test --workspace --all-features`, `cargo deny check licenses` — all green.

**BREAKING for Python**: batch return types change from NumPy arrays to `array.array`/`Matrix`. Documented in CHANGELOG; ships with the data-layer release bundle (no separate tag).

Cargo.lock

@@ -100,6 +100,12 @@ version = "3.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
 
+[[package]]
+name = "bytemuck"
+version = "1.25.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8efb64bd706a16a1bdde310ae86b351e4d21550d98d056f22f8a7f7a2183fec"
+
 [[package]]
 name = "bytes"
 version = "1.11.1"
@@ -716,16 +722,6 @@ version = "0.4.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5e5032e24019045c762d3c0f28f5b6b8bbf38563a65908389bf7978758920897"
 
-[[package]]
-name = "matrixmultiply"
-version = "0.3.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a06de3016e9fae57a36fd14dba131fccf49f74b40b7fbdb472f96e361ec71a08"
-dependencies = [
- "autocfg",
- "rawpointer",
-]
-
 [[package]]
 name = "memchr"
 version = "2.8.0"
@@ -827,21 +823,6 @@ dependencies = [
  "tempfile",
 ]
 
-[[package]]
-name = "ndarray"
-version = "0.16.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "882ed72dce9365842bf196bdeedf5055305f11fc8c03dee7bb0194a6cad34841"
-dependencies = [
- "matrixmultiply",
- "num-complex",
- "num-integer",
- "num-traits",
- "portable-atomic",
- "portable-atomic-util",
- "rawpointer",
-]
-
 [[package]]
 name = "nu-ansi-term"
 version = "0.50.3"
@@ -851,24 +832,6 @@ dependencies = [
  "windows-sys",
 ]
 
-[[package]]
-name = "num-complex"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "73f88a1307638156682bada9d7604135552957b7818057dcef22705b4d509495"
-dependencies = [
- "num-traits",
-]
-
-[[package]]
-name = "num-integer"
-version = "0.1.46"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7969661fd2958a5cb096e56c8e1ad0444ac2bbcd0061bd28660485a44879858f"
-dependencies = [
- "num-traits",
-]
-
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -901,22 +864,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "numpy"
-version = "0.29.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a5b15d63a5ff39e378daed0e1340d3a5964703ea9712eb09a0dc66fade996f4"
-dependencies = [
- "libc",
- "ndarray",
- "num-complex",
- "num-integer",
- "num-traits",
- "pyo3",
- "pyo3-build-config",
- "rustc-hash",
-]
-
 [[package]]
 name = "once_cell"
 version = "1.21.4"
@@ -1034,15 +981,6 @@ version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c33a9471896f1c69cecef8d20cbe2f7accd12527ce60845ff44c153bb2a21b49"
 
-[[package]]
-name = "portable-atomic-util"
-version = "0.2.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2a106d1259c23fac8e543272398ae0e3c0b8d33c88ed73d0cc71b0f1d902618"
-dependencies = [
- "portable-atomic",
-]
-
 [[package]]
 name = "potential_utf"
 version = "0.1.5"
@@ -1214,12 +1152,6 @@ dependencies = [
  "rand_core",
 ]
 
-[[package]]
-name = "rawpointer"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60a357793950651c4ed0f3f52338f53b2f809f32d83a07f72909fa13e4c6c1e3"
-
 [[package]]
 name = "rayon"
 version = "1.12.0"
@@ -1269,12 +1201,6 @@ version = "0.8.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc897dd8d9e8bd1ed8cdad82b5966c3e0ecae09fb1907d58efaa013543185d0a"
 
-[[package]]
-name = "rustc-hash"
-version = "2.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94300abf3f1ae2e2b8ffb7b58043de3d399c73fa6f4b73826402a5c457614dbe"
-
 [[package]]
 name = "rustix"
 version = "1.1.4"
@@ -1934,7 +1860,7 @@ dependencies = [
 name = "wickra-python"
 version = "0.9.2"
 dependencies = [
- "numpy",
+ "bytemuck",
  "pyo3",
  "tokio",
  "wickra-core",