1.0.0-alpha.1

Ground-up rewrite of VTracer into a **vectorization framework** with pluggable stages.

### Added

* Pluggable pipeline: swappable frontend (segmentation), color fitting (incl. custom palettes), curve-fitting backend, and an optimizer pass phase.
* **Mosaic mode**: true seam-free, gapless tessellation via shared boundary-graph tracing (pixel, polygon, and spline fitters), replacing the old "cutout" that produced seams.
* SVG optimizer: relative path syntax, shorthand commands, and coordinate-precision reduction for smaller files.
* `@visioncortex/vtracer` Node.js package (npm): wasm core with a native image reader.
* Rewritten Python bindings (`vtracer-py`) with a richer API; pyo3 bumped to 0.26 (fixes CPython 3.14 segfaults, #124).
* CLI accepts positional `input`/`output` arguments (#114).

### Changed

* Workspace restructured into `crates/vtracer` (core lib), `crates/vtracer-cli`, `crates/vtracer-py`, and `nodejs/`.
* CLI upgraded from clap 2.x to 4.x (#118).
* `filter_speckle` CLI cap raised from 16 to 128, matching the web app (#115).
* Depends on `visioncortex` 0.9.
* Python wheel CI now runs only on release tags and manual dispatch, not on every commit.