refactor: rename to Stann\Stream, split 1-file-per-function, add missing ops, remove stream()

- Rename namespace Collect → Stann\Stream, package camille/collect → stann/stream
- Split monolithic functions.php into Transformations/ (21) and Terminators/ (14)
- Add: takeWhile, skipWhile, concat, enumerate, scan, partition, min, max, tap
- Remove stream() entry point — arrays and generators work directly with pipe
- Add docs/API.md with full reference, rewrite README with links and custom steps section

Author: camillebaronnet

README.md

@@ -1,6 +1,6 @@
 {
-    "name": "camille/collect",
-    "description": "Pipe-native collection functions for PHP 8.5+. Curried, lazy, zero-wrapper.",
+    "name": "stann/stream",
+    "description": "Pipe-native stream functions for PHP 8.5+. Curried, lazy, zero-wrapper.",
     "type": "library",
     "license": "MIT",
     "minimum-stability": "stable",
@@ -19,7 +19,7 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "Collect\\Tests\\": "tests/"
+            "Stann\\Stream\\Tests\\": "tests/"
         }
     },
     "scripts": {