Add changelog entries and restore multi-line WhatsApp error log

Add changelog entries for the pyright introduction and the
LiveKitRunnerArguments.token signature tightening. Restore the
indented multi-line format for the WhatsApp missing-env error,
now listing only the vars that are actually missing.

changelog/4324.added.md

@@ -0,0 +1 @@
+- Added incremental `pyright` type checking. A `pyrightconfig.json` at the repo root uses `typeCheckingMode: "basic"` with an explicit `include` list of modules that pass cleanly (`clocks`, `metrics`, `transcriptions`, `frames`, `observers`, `extensions`, `turns`, `pipeline`, `runner`). Remaining modules will be added in subsequent PRs. CI enforces the checked set via `uv run pyright` in the format workflow.

changelog/4324.changed.md

@@ -0,0 +1 @@
+- `LiveKitRunnerArguments.token` is now a required `str` (previously `str | None` with a default of `None`). LiveKit requires a token to join a room, so the type now reflects reality. This only affects custom runners that construct `LiveKitRunnerArguments` directly; code consuming the argument from the standard runner is unaffected.

src/pipecat/runner/run.py

@@ -396,8 +396,11 @@ def _setup_whatsapp_routes(app: FastAPI, args: argparse.Namespace):
     ]
     missing = [v for v in required_vars if not os.getenv(v)]
     if missing:
+        missing_list = "\n    ".join(missing)
         logger.error(
-            f"Missing required environment variables for WhatsApp transport: {', '.join(missing)}"
+            f"""Missing required environment variables for WhatsApp transport:
+    {missing_list}
+            """
         )
         return