Samples - Add samples directory (#1257)

- Added `samples/README.md` describing where OCCT sample applications/wrappers are maintained (external repository + browsable site).
- Updated root `.gitignore` whitelist to allow tracking the `/samples/` directory at repository root.

.gitignore

@@ -20,8 +20,8 @@
 !/dox/
 !/src/
 !/tests/
-!/tools/
 !/.github/
+!/samples/
 
 # data/ level: Ignore everything except tracked subdirectories
 /data/*

samples/README.md

@@ -0,0 +1,20 @@
+# OCCT Samples
+
+The community-maintained registry of OCCT-based projects, sample apps,
+libraries, and language wrappers lives in its own repository:
+
+**[Open-Cascade-SAS/OCCT-Samples](https://github.com/Open-Cascade-SAS/OCCT-Samples)**
+([browsable site](https://open-cascade-sas.github.io/OCCT-Samples/))
+
+There you'll find:
+
+- Open-source applications and viewers built on OCCT
+- Sample apps in their own repositories (C#, Kotlin, ...)
+- Language wrappers (Python, JavaScript, ...)
+- Libraries that consume OCCT
+- Schema, taxonomy, and a structured GitHub issue flow for proposing
+  your own project
+
+For the **commercial** OCCT extensions maintained by Open Cascade SAS,
+see [Open-Cascade-SAS/OCCT-Components](https://github.com/Open-Cascade-SAS/OCCT-Components)
+and [occt3d.com/components](https://occt3d.com/components/).