feat: IRC — add first-class channel support

Adds IRC as a first-class channel with core config surfaces (schema/hints/dock), plugin auto-enable detection, routing/policy alignment, and docs/tests.

Co-authored-by: Vignesh <vigneshnatarajan92@gmail.com>

extensions/irc/src/control-chars.ts

@@ -0,0 +1,22 @@
+export function isIrcControlChar(charCode: number): boolean {
+  return charCode <= 0x1f || charCode === 0x7f;
+}
+
+export function hasIrcControlChars(value: string): boolean {
+  for (const char of value) {
+    if (isIrcControlChar(char.charCodeAt(0))) {
+      return true;
+    }
+  }
+  return false;
+}
+
+export function stripIrcControlChars(value: string): string {
+  let out = "";
+  for (const char of value) {
+    if (!isIrcControlChar(char.charCodeAt(0))) {
+      out += char;
+    }
+  }
+  return out;
+}