Add CUPS printing system bindings to c.s.j.p.unix

Closes #1710

Add Cups interface providing JNA bindings for libcups, the Common UNIX
Printing System library. Includes structures (CupsDest, CupsOption,
CupsJob), printer state/type constants, job state constants, and
functions for destination enumeration, job management, option handling,
and server/user configuration.

Author: dbwiddis

CHANGES.md

@@ -9,6 +9,7 @@ Features
 --------
 * [#1696](https://github.com/java-native-access/jna/pull/1696): Add `LARGE_INTEGER.ByValue` to `LARGE_INTEGER` in `WinNT.java` - [@baier233](https://github.com/baier233).
 * [#1697](https://github.com/java-native-access/jna/pull/1697): Add WlanApi module - [@eranl](https://github.com/eranl).
+* [#1718](https://github.com/java-native-access/jna/pull/1718): Add `Cups` to `c.s.j.p.unix` providing CUPS printing system bindings for destinations, jobs, options, and server configuration - [@dbwiddis](https://github.com/dbwiddis).
 
 Bug Fixes
 ---------

PR_DESCRIPTION.md

@@ -0,0 +1,43 @@
+## Add CUPS printing system bindings
+
+Closes #1710
+
+Adds `Cups` interface to `c.s.j.p.unix` providing JNA bindings for [libcups](https://openprinting.github.io/cups/doc/cupspm.html), the Common UNIX Printing System library available on Linux, macOS, and other UNIX platforms.
+
+### Structures
+
+| Structure | C type | Description |
+|-----------|--------|-------------|
+| `CupsDest` | `cups_dest_t` | Printer/class destination with name, instance, and options |
+| `CupsOption` | `cups_option_t` | Name/value option pair |
+| `CupsJob` | `cups_job_t` | Print job with ID, state, title, user, and timestamps |
+
+### Functions
+
+| Function | Description |
+|----------|-------------|
+| `cupsGetDests` / `cupsGetDests2` | Enumerate available printers |
+| `cupsFreeDests` | Free destination list |
+| `cupsGetDest` | Find a printer in a list by name |
+| `cupsGetNamedDest` | Optimized single-printer lookup |
+| `cupsGetDefault` | Get default printer name |
+| `cupsGetOption` | Read an option value |
+| `cupsAddOption` | Add/replace an option |
+| `cupsFreeOptions` | Free options array |
+| `cupsGetJobs2` | Get print jobs (active/completed/all) |
+| `cupsFreeJobs` | Free job array |
+| `cupsCancelJob` | Cancel a print job |
+| `cupsServer` / `cupsSetServer` | Get/set CUPS server |
+| `cupsUser` / `cupsSetUser` | Get/set CUPS user |
+| `cupsLastError` / `cupsLastErrorString` | Error reporting |
+
+### Constants
+
+- Printer state: `IPP_PRINTER_IDLE`, `IPP_PRINTER_PROCESSING`, `IPP_PRINTER_STOPPED`
+- Printer type flags: `CUPS_PRINTER_CLASS`, `CUPS_PRINTER_COLOR`, `CUPS_PRINTER_DUPLEX`, etc.
+- Job state: `IPP_JSTATE_PENDING` through `IPP_JSTATE_COMPLETED`
+- Job filters: `CUPS_WHICHJOBS_ALL`, `CUPS_WHICHJOBS_ACTIVE`, `CUPS_WHICHJOBS_COMPLETED`
+
+### Testing
+
+`CupsTest` exercises all functions, gracefully handling environments without CUPS installed or without a running scheduler.