feat: strip IRC formatting codes from messages sent to Owncast

Add irc_format module that removes mIRC control codes (bold, color,
italic, underline, reverse, strikethrough, monospace, reset) before
forwarding to Owncast. Color codes with fg/bg digit params are
consumed correctly. Multi-byte UTF-8 (emoji, accented chars, CJK)
is preserved.

Made-with: Cursor

chat-summaries/2026-03-12_strip-irc-formatting-summary.md

@@ -0,0 +1,17 @@
+# Strip IRC Formatting Codes from Owncast-bound Messages
+
+**Date:** 2026-03-12
+
+## Task
+
+IRC messages forwarded to Owncast contained mIRC formatting control codes (`\x02`, `\x03`, `\x0F`, etc.) that rendered as garbage glyphs since Owncast doesn't support any message styling.
+
+## Changes
+
+- **New file: `src/irc_format.rs`** — `strip_formatting()` function that removes all IRC formatting control codes: bold, color (with fg/bg digit parameters), reset, monospace, reverse, italic, strikethrough, and underline. Includes 18 unit tests.
+- **`src/irc_task.rs`** — Call `strip_formatting()` on the message body before constructing the `BridgeEvent`, so all downstream consumers see clean text.
+- **`src/main.rs`** — Registered the new `irc_format` module.
+
+## Follow-up
+
+- None identified. No new dependencies added.