feat(lang): friend module lab of fishing, data - a friend of the modules it names

A scoped friend sees those modules' private names and only the exports
of every other; a plain friend module still sees everything. Reseed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/modules/friend_of.ludic

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+# friend_of.ludic — L3: `friend module lab of bank` sees bank's private names and no other module's;
+# a test harness reaches inside exactly what it tests. `friend module lab` alone still sees all.
+#
+# Running it prints:  7 7
+import "bank"
+program FriendOf {
+  friend module lab of bank
+  entry {
+    add(7)
+    print(`{balance} {total()}`)
+  }
+}

examples/rejected/friend_scope.ludic

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+# L3: a friend of kit is not a friend of bank - bank's private `add` stays out of reach
+import "private_bank"
+import "private_kit"
+program FriendScope {
+  friend module lab of kit
+  entry {
+    add(5)
+    print(total())
+  }
+}