Replace the C++ implementation with the Rust port

The Rust port (formerly gipfel-rs) is now the official successor to the
FLTK/GSL C++ code base. This squashes the port into a single commit and
removes the C++ sources (they remain in the git history below).

Layout:
  crates/gipfel-core  headless core: hills, panorama geometry, projections
                      (maxima-generated derivatives), pure-Rust LM fit,
                      gipfel: JPEG comment + EXIF I/O, profiles, stitching
  crates/gipfel-cli   command-line tools (export, info, stitch, profiles)
  crates/gipfel-app   Cosmic DE (libcosmic) GUI, binary name `gipfel`
  codegen/            maxima scripts + regen.sh for the projection code
  tests/              golden files + C++ reference harnesses (historical)

The original README is kept for now; it will be updated to describe the
Rust build. gipfel.dat, AUTHORS, ChangeLog and NEWS are unchanged.

1 files changed, 23 insertions, 0 deletions

diff --git a/crates/gipfel-core/src/lib.rs b/crates/gipfel-core/src/lib.rs
new file mode 100644
index 0000000..2e2fac9
--- /dev/null
+++ b/crates/gipfel-core/src/lib.rs
@@ -0,0 +1,23 @@
+//! gipfel-core: headless port of the gipfel computational core.
+//!
+//! Modules:
+//! - [`hill`]: hill database (CSV load, duplicate marking)
+//! - [`panorama`]: viewpoint, geodesy, refraction, occlusion, visibility
+//! - [`projection`]: rectilinear/cylindrical projections with symbolic
+//!   derivatives generated by maxima (see `codegen/`)
+//! - [`lsq`]: Levenberg-Marquardt fit of the view parameters (system GSL)
+//! - [`metadata`]: `gipfel:` JPEG comment + EXIF read/write
+
+pub mod hill;
+pub mod lsq;
+pub mod metadata;
+pub mod panorama;
+pub mod profile;
+pub mod projection;
+pub mod stitch;
+pub mod track;
+
+pub use hill::Hill;
+pub use metadata::ImageMetaData;
+pub use panorama::Panorama;
+pub use projection::{Projection, ProjectionType, ViewParams};