#7404: feat(slack): add Socket Mode bot + auto-join + bridge scaffolding; ad…

…d SMTP sender; env example updates <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> Adds two new root-level utility scripts: a Slack Socket Mode bot scaffold (`scripts/slack-bot.js`) and an SMTP sender helper (`scripts/send-email.js`), and wires them into `package.json` as `pnpm slack:run` and `pnpm send:email`. Also introduces `nodemailer` as a dependency (lockfile updated accordingly). These scripts are currently standalone tooling under `scripts/` rather than integrated into `src/` channel implementations, providing a quick way to prototype Slack event handling and send outbound email from the repo. <h3>Confidence Score: 4/5</h3> - This PR is mostly safe to merge; the main concerns are operational/safety defaults in the Slack bot script rather than core runtime changes. - Changes are additive and isolated to new scripts plus a single new dependency. The biggest issues are that the Slack script currently logs event payloads and auto-joins all public channels by default, which can cause data leakage/noise/rate limits if someone runs it in a real workspace. No deeper cross-cutting code paths were modified. - scripts/slack-bot.js <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->