chore(slack): remove dead invite path, archive checkSlackJoins poller

Wave-based onboarding makes the auto-invite + polling path obsolete.

- Removes SlackService.inviteUserToSlack — admins now send invites
  through Slack's UI and flip the flag in our admin endpoint.
- Removes the slack_invite_failed admin alert + its detector. The
  alert no longer has a meaningful trigger (we don't attempt invites).
- Archives server/utils/checkSlackJoins.js (and its test) under
  _archive/ in case the polling pattern is needed again post-pilot.
- Deletes the Nitro plugin that scheduled checkSlackJoins on boot
  + hourly. Nothing in nitro.config / nuxt.config / package.json
  registered it elsewhere.
- Drops the slack_invite_failed branch from adminAlerts.test; the
  enum slug stays in adminAlertDismissal so historical dismissal
  rows continue to validate.

notifyNewMember (vetting-channel notification) and findUserByEmail
(used by the auto-flag helper) are retained.

server/plugins/check-slack-joins.js

@@ -1,29 +0,0 @@
-// server/plugins/check-slack-joins.js
-import { checkSlackJoins } from '../utils/checkSlackJoins.js'
-
-const INTERVAL_MS = 3600000 // 1 hour
-
-export default defineNitroPlugin(() => {
-  // Don't run in test environment
-  if (process.env.NODE_ENV === 'test') return
-
-  const config = useRuntimeConfig()
-  const token = config.slackBotToken
-
-  if (!token) {
-    console.warn('[check-slack-joins] No Slack bot token configured, skipping background job')
-    return
-  }
-
-  async function run() {
-    try {
-      await checkSlackJoins(token)
-    } catch (err) {
-      console.error('[check-slack-joins] Unhandled error:', err.message || err)
-    }
-  }
-
-  // Run immediately on server start, then every hour
-  run()
-  setInterval(run, INTERVAL_MS)
-})

server/utils/adminAlerts.js

@@ -17,7 +17,6 @@ export const ALERT_THRESHOLDS = {
 // Single source of truth for alert presentation. Used by detectors AND the
 // dismissed-list endpoint (which has no access to a detector run's output).
 export const ALERT_METADATA = {
-  slack_invite_failed: { title: 'Slack invites failed', severity: 'critical' },
   no_slack_handle_week: { title: 'Active members without a Slack handle', severity: 'attention' },
   stuck_pending_payment: { title: 'Members stuck in pending payment', severity: 'attention' },
   member_suspended: { title: 'Suspended members', severity: 'attention' },
@@ -62,18 +61,6 @@ function memberItem(member, sublabel) {
   }
 }
 
-export async function detectSlackInviteFailed() {
-  await connectDB()
-  const members = await Member
-    .find({ slackInviteStatus: 'failed' })
-    .select('name email')
-    .lean()
-  return {
-    ...alertShell('slack_invite_failed'),
-    items: members.map((m) => memberItem(m))
-  }
-}
-
 export async function detectNoSlackHandleAfterWeek() {
   await connectDB()
   const cutoff = daysAgo(ALERT_THRESHOLDS.NO_SLACK_DAYS)
@@ -257,7 +244,6 @@ export async function detectPendingTagSuggestions() {
 }
 
 const DETECTORS = [
-  detectSlackInviteFailed,
   detectNoSlackHandleAfterWeek,
   detectStuckPendingPayment,
   detectSuspendedMembers,

server/utils/slack.ts

@@ -9,98 +9,6 @@ export class SlackService {
     this.vettingChannelId = vettingChannelId;
   }
 
-  /**
-   * Invite user to workspace and channel (using proper admin and conversation scopes)
-   */
-  async inviteUserToSlack(
-    email: string,
-    realName: string,
-  ): Promise<{
-    success: boolean;
-    userId?: string;
-    status?: string;
-    error?: string;
-  }> {
-    try {
-      // First, check if user already exists in workspace
-      const existingUser = await this.findUserByEmail(email);
-
-      if (existingUser) {
-        // User exists, invite them to the vetting channel
-        try {
-          await this.client.conversations.invite({
-            channel: this.vettingChannelId,
-            users: existingUser,
-          });
-
-          console.log(
-            `Successfully invited existing user ${email} to vetting channel`,
-          );
-          return {
-            success: true,
-            userId: existingUser,
-            status: "existing_user_added_to_channel",
-          };
-        } catch (error: any) {
-          if (error.data?.error === "already_in_channel") {
-            return {
-              success: true,
-              userId: existingUser,
-              status: "user_already_in_channel",
-            };
-          }
-          throw error;
-        }
-      }
-
-      // User doesn't exist, try to invite to workspace using admin API
-      try {
-        const inviteResponse = await this.client.admin.users.invite({
-          email: email,
-          real_name: realName,
-          channel_ids: [this.vettingChannelId],
-          is_restricted: true, // Single-channel guest
-          is_ultra_restricted: false,
-        });
-
-        if (inviteResponse.ok && inviteResponse.user) {
-          console.log(
-            `Successfully invited ${email} to workspace as single-channel guest`,
-          );
-          return {
-            success: true,
-            userId: inviteResponse.user.id,
-            status: "new_user_invited_to_workspace",
-          };
-        } else {
-          throw new Error(`Admin invite failed: ${inviteResponse.error}`);
-        }
-      } catch (adminError: any) {
-        console.log(
-          `Admin API not available or failed: ${
-            adminError.data?.error || adminError.message
-          }`,
-        );
-
-        // Fall back to manual process
-        return {
-          success: true,
-          status: "manual_invitation_required",
-          error: `Admin API unavailable: ${
-            adminError.data?.error || adminError.message
-          }`,
-        };
-      }
-    } catch (error: any) {
-      console.error(`Failed to process invitation for ${email}:`, error);
-
-      return {
-        success: false,
-        error: error.data?.error || error.message || "Unknown error occurred",
-      };
-    }
-  }
-
   /**
    * Find user in workspace by email
    */