Add 105 proof files across all pattern categories

Co-authored-by: brunoborges <129743+brunoborges@users.noreply.github.com>

Author: Copilot

proof/collections/CollectorsTeeing.java

@@ -0,0 +1,19 @@
+import java.util.*;
+import java.util.stream.*;
+import static java.util.stream.Collectors.*;
+
+/// Proof: collectors-teeing
+/// Source: content/collections/collectors-teeing.yaml
+record Item(String name, double price) {}
+record Stats(long count, double total) {}
+
+void main() {
+    var items = List.of(new Item("a", 10.0), new Item("b", 20.0));
+    var result = items.stream().collect(
+        Collectors.teeing(
+            Collectors.counting(),
+            Collectors.summingDouble(Item::price),
+            Stats::new
+        )
+    );
+}

proof/collections/CopyingCollectionsImmutably.java

@@ -0,0 +1,9 @@
+import java.util.*;
+
+/// Proof: copying-collections-immutably
+/// Source: content/collections/copying-collections-immutably.yaml
+void main() {
+    List<String> original = new ArrayList<>(List.of("a", "b", "c"));
+    List<String> copy =
+        List.copyOf(original);
+}

proof/collections/ImmutableListCreation.java

@@ -0,0 +1,8 @@
+import java.util.*;
+
+/// Proof: immutable-list-creation
+/// Source: content/collections/immutable-list-creation.yaml
+void main() {
+    List<String> list =
+        List.of("a", "b", "c");
+}

proof/collections/ImmutableMapCreation.java

@@ -0,0 +1,8 @@
+import java.util.*;
+
+/// Proof: immutable-map-creation
+/// Source: content/collections/immutable-map-creation.yaml
+void main() {
+    Map<String, Integer> map =
+        Map.of("a", 1, "b", 2, "c", 3);
+}

proof/collections/ImmutableSetCreation.java

@@ -0,0 +1,8 @@
+import java.util.*;
+
+/// Proof: immutable-set-creation
+/// Source: content/collections/immutable-set-creation.yaml
+void main() {
+    Set<String> set =
+        Set.of("a", "b", "c");
+}

proof/collections/MapEntryFactory.java

@@ -0,0 +1,7 @@
+import java.util.*;
+
+/// Proof: map-entry-factory
+/// Source: content/collections/map-entry-factory.yaml
+void main() {
+    var e = Map.entry("key", 42);
+}

proof/collections/ReverseListIteration.java

@@ -0,0 +1,10 @@
+import java.util.*;
+
+/// Proof: reverse-list-iteration
+/// Source: content/collections/reverse-list-iteration.yaml
+void main() {
+    List<String> list = List.of("a", "b", "c");
+    for (String element : list.reversed()) {
+        System.out.println(element);
+    }
+}

proof/collections/SequencedCollections.java

@@ -0,0 +1,10 @@
+import java.util.*;
+
+/// Proof: sequenced-collections
+/// Source: content/collections/sequenced-collections.yaml
+void main() {
+    List<String> list = new ArrayList<>(List.of("a", "b", "c"));
+    var last = list.getLast();
+    var first = list.getFirst();
+    var reversed = list.reversed();
+}

proof/collections/StreamToarrayTyped.java

@@ -0,0 +1,14 @@
+import java.util.*;
+import java.util.stream.*;
+
+/// Proof: stream-toarray-typed
+/// Source: content/collections/stream-toarray-typed.yaml
+List<String> getNames() {
+    return List.of("Alice", "Bob", "Charlie", "Dave");
+}
+
+void main() {
+    String[] arr = getNames().stream()
+        .filter(n -> n.length() > 3)
+        .toArray(String[]::new);
+}

proof/collections/UnmodifiableCollectors.java

@@ -0,0 +1,9 @@
+import java.util.*;
+import java.util.stream.*;
+
+/// Proof: unmodifiable-collectors
+/// Source: content/collections/unmodifiable-collectors.yaml
+void main() {
+    Stream<String> stream = Stream.of("a", "b", "c");
+    List<String> list = stream.toList();
+}