release(v1.1.0): additive CPU-only generic numerical primitives

Adds 9 new top-level / sub-modules to the Rust API only (no Python
bindings yet), with at least one analytic unit test per module.

New Rust modules:
- optimal_control::matrix_riccati  (RK4 backward solver)
- timeseries_utils::nonsync_covariance  (Hayashi-Yoshida)
- timeseries_utils::wavelet  (Haar / Daubechies DWT and MODWT)
- risk_measures  (VaR, CVaR, projected sub-gradient CVaR minimisation)
- graph::laplacian + graph::spectral_clustering  (Jacobi + k-means++)
- topology  (Vietoris-Rips persistent homology, bottleneck distance)
- volterra  (Caputo Adams, Markovian lift, second-kind Volterra,
             Fourier inversion of characteristic functions)
- signatures  (truncated tensor signature, log-sig, random reservoir,
               Salvi-Cass-Lyons signature kernel, shuffle product)

All previously stable APIs untouched; abi3-py38 ABI preserved.
New module tests: 29/29 passing. Pre-existing 5 unrelated failures
unchanged.

CHANGELOG.md

@@ -0,0 +1,60 @@
+# Changelog
+
+All notable changes to **optimiz-rs** are documented in this file. The format
+follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) and the project
+adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [1.1.0] - 2026-05-12
+
+### Added — purely additive, no existing API changes
+
+- `optimal_control::matrix_riccati` — RK4 backward solver for the
+  matrix Riccati differential equation
+  `dA/dt = -2 A M A + Q`, plus terminal-condition variants for the
+  associated affine and constant components.
+- `timeseries_utils::nonsync_covariance` — Hayashi--Yoshida estimator
+  for asynchronous covariance, with parallel matrix variant.
+- `timeseries_utils::wavelet` — discrete and maximum-overlap wavelet
+  transforms (Haar, Daubechies orders 2--10) with periodic boundaries.
+- `risk_measures` — empirical and parametric Value-at-Risk and
+  Conditional Value-at-Risk estimators, plus a projected sub-gradient
+  solver for convex CVaR minimisation over the unit simplex.
+- `graph::laplacian` — combinatorial, symmetric-normalised and
+  random-walk graph Laplacians.
+- `graph::spectral_clustering` — spectral clustering via Jacobi
+  diagonalisation and Lloyd's algorithm with k-means++ initialisation.
+- `topology::persistent_homology` — Vietoris--Rips persistent homology
+  by the standard `Z/2` matrix-reduction algorithm.
+- `topology::bottleneck` — bottleneck distance between persistence
+  diagrams via Hopcroft--Karp matching with binary search.
+- `volterra::fractional_riccati` — Adams predictor--corrector solver
+  for Caputo fractional ODEs (Diethelm--Ford--Freed 2002).
+- `volterra::markovian_lift` — multi-exponential approximation of
+  convolution kernels by non-negative least squares on a geometric
+  grid.
+- `volterra::volterra_solver` — generic second-kind Volterra integral
+  equation solver via product-trapezoidal quadrature.
+- `volterra::fourier_inversion` — direct trapezoidal Fourier inversion
+  of a characteristic function on a uniform frequency grid.
+- `signatures::path_signature` — truncated tensor signature of a
+  piecewise-linear path with truncated tensor exponential.
+- `signatures::log_signature` — truncated tensor logarithm of a
+  signature.
+- `signatures::random_signature` — Cuchiero--Schmocker--Teichmann
+  random reservoir projection of the signature.
+- `signatures::signature_kernel` — Salvi--Cass--Lyons signature kernel
+  via the Goursat finite-difference scheme.
+- `signatures::utils` — shuffle product and Chen-identity-driven
+  signature concatenation.
+
+### Changed
+
+- Bumped crate version from `1.0.1` to `1.1.0`. All previously stable
+  symbols remain untouched and binary-compatible at the Python ABI
+  level (`abi3-py38`).
+
+### Notes
+
+This release is **CPU-only and additive**. No Python bindings were added
+in `1.1.0`; the new modules are exposed via the Rust API only and will
+be wrapped behind the `python-bindings` feature in a follow-up release.