feat: add plug-and-play devRant API client examples with Python and JavaScript

Add complete set of example scripts for the devRant REST protocol under
examples/devrant/, including reusable client libraries, a rant poster,
a live feed watcher with keyword-based auto-upvote, and an end-to-end
smoke test that exercises every endpoint. Both Python (stdlib-only) and
JavaScript (Node 18+ global fetch) implementations are provided.

examples/devrant/feed_watch.py

@@ -0,0 +1,39 @@
+# retoor <retoor@molodetz.nl>
+
+import os
+import time
+
+from client import from_env
+
+POLL_SECONDS = int(os.environ.get("DEVRANT_POLL_SECONDS", "30"))
+UPVOTE_KEYWORDS = [
+    word.strip().lower()
+    for word in os.environ.get("DEVRANT_UPVOTE_KEYWORDS", "").split(",")
+    if word.strip()
+]
+
+
+def main() -> None:
+    api = from_env()
+    if api.username and api.password:
+        api.login()
+    seen: set[int] = set()
+    print(f"watching feed every {POLL_SECONDS}s (ctrl-c to stop)")
+    while True:
+        for rant in reversed(api.rants(sort="recent", limit=20)):
+            rant_id = rant["id"]
+            if rant_id in seen:
+                continue
+            seen.add(rant_id)
+            text = rant["text"].replace("\n", " ")[:80]
+            print(f"[{rant_id}] {rant['user_username']}: {text}")
+            if UPVOTE_KEYWORDS and api.auth:
+                lowered = rant["text"].lower()
+                if any(word in lowered for word in UPVOTE_KEYWORDS):
+                    api.vote_rant(rant_id, 1)
+                    print(f"  upvoted {rant_id}")
+        time.sleep(POLL_SECONDS)
+
+
+if __name__ == "__main__":
+    main()