feat: initial Beta 1 release

- soju raw connector with event playback and CHATHISTORY fallback
- SQLite store with msgid de-dup and retention job
- Mentions + Pushover + tuning; structured JSON logs
- Summaries: concise, link-following, multi-line grouping
- HTTP: /healthz, /ready, /tail, /trigger, /metrics
- Docker: distroless, healthcheck, version metadata
- Docs: README, CHANGELOG, compose

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## Beta 1 (initial release)
+- soju-specific raw connector with event playback and CHATHISTORY fallback
+- Message storage (SQLite, WAL), msgid de-dup, retention job
+- Mentions with tuning (quiet hours, rate limiting, allow/deny, urgent keywords)
+- Pushover notifications
+- OpenAI summarization: concise natural summaries, link-following, multi-line grouping
+- HTTP: /healthz, /ready, /tail, /trigger, /metrics (connected gauge and counters)
+- Structured JSON logs (slog)
+- Docker: distroless, built-in healthcheck, version/commit injected
+
+## Unreleased
+- Additional notifiers (ntfy, Telegram)
+- Long-form HTML digest rendering
+- Admin endpoints (e.g., /join)