Capture member/filter/spam events for the dashboard (Phase 6b)

Light up the moderation dashboard's previously-empty widgets by persisting the
event streams the bot only reacted to in-memory before.

Schema (bot-owned)
- member_events: join/leave, with invite_code/inviter_* for best-effort invite
  attribution on joins
- filter_hits: word / foreign-invite filter deletions (matched + action_taken)
- spam_hits: rate_limit / mass_mention / mass_emoji detections

Bot
- new models memberEvents/filterHits/spamHits
- guildMemberAdd records the join with invite attribution; new inviteTracker.js
  keeps an invite-use cache (GuildInvites intent + inviteCreate/inviteDelete) and
  diffs it on join to find which invite was used — best-effort, never blocks
  auto-role
- new guildMemberRemove records leaves
- messageFilter records filter/spam hits alongside the existing warn/mute;
  inviteFilter now returns the offending code; detectSpam identifies which spam
  rule tripped (preserving the rate-limit-first side-effect order)
- mod_actions still logs the resulting warn/mute — the new tables are additive

Server
- summary extended with joins/leaves/invite_joins/filter_hits/spam_hits per window
- new feeds: /api/v1/admin/moderation/{members,filter-hits,spam-hits}

Client
- overview now shows 8 tiles (mod actions + joins/leaves/filter/spam, joins tile
  notes "N via invite") plus an Events panel with Members/Filter/Spam tabs;
  removed the coming-soon note

Verified: 119 server unit tests, client build, 14-check DB-backed smoke, and a
browser click-through of every tile and events tab (incl. invite attribution).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019rao86n5cXpwAyjdBFEshV

server/src/model/moderation/moderation.db.js

@@ -89,6 +89,70 @@ async function linkedAccount(discordId) {
   return rows[0] || null
 }
 
+// ── Phase 6b: member events + filter/spam hits (bot-owned, read-only) ──
+
+// Join/leave counts per window (grouped by event_type).
+async function memberCountsByWindow({ cutoff24h, cutoff7d, cutoff30d }) {
+  return query(
+    `SELECT event_type,
+            SUM(created_at >= ?) AS d1,
+            SUM(created_at >= ?) AS d7,
+            SUM(created_at >= ?) AS d30
+       FROM member_events
+      WHERE created_at >= ?
+      GROUP BY event_type`,
+    [cutoff24h, cutoff7d, cutoff30d, cutoff30d],
+  )
+}
+
+// Attributed-invite join counts per window (joins whose invite we identified).
+async function inviteJoinCountsByWindow({ cutoff24h, cutoff7d, cutoff30d }) {
+  const rows = await query(
+    `SELECT SUM(created_at >= ?) AS d1, SUM(created_at >= ?) AS d7, SUM(created_at >= ?) AS d30
+       FROM member_events
+      WHERE event_type = 'join' AND invite_code IS NOT NULL AND created_at >= ?`,
+    [cutoff24h, cutoff7d, cutoff30d, cutoff30d],
+  )
+  return rows[0]
+}
+
+// Row-count per window for a simple event table. `table` is an internal literal
+// ('filter_hits' | 'spam_hits'), never user input — see the caller allowlist.
+async function tableCountsByWindow(table, { cutoff24h, cutoff7d, cutoff30d }) {
+  const rows = await query(
+    `SELECT SUM(created_at >= ?) AS d1, SUM(created_at >= ?) AS d7, SUM(created_at >= ?) AS d30
+       FROM ${table} WHERE created_at >= ?`,
+    [cutoff24h, cutoff7d, cutoff30d, cutoff30d],
+  )
+  return rows[0]
+}
+
+async function recentMemberEvents({ type = null, limit = 50, offset = 0 } = {}) {
+  const where = type ? 'WHERE event_type = ?' : ''
+  const params = type ? [type, limit, offset] : [limit, offset]
+  return query(
+    `SELECT id, guild_id, event_type, discord_user_id, username, invite_code, inviter_id, inviter_tag, created_at
+       FROM member_events ${where} ORDER BY id DESC LIMIT ? OFFSET ?`,
+    params,
+  )
+}
+
+async function recentFilterHits({ limit = 50, offset = 0 } = {}) {
+  return query(
+    `SELECT id, guild_id, hit_type, discord_user_id, username, channel_id, matched, action_taken, created_at
+       FROM filter_hits ORDER BY id DESC LIMIT ? OFFSET ?`,
+    [limit, offset],
+  )
+}
+
+async function recentSpamHits({ limit = 50, offset = 0 } = {}) {
+  return query(
+    `SELECT id, guild_id, spam_type, discord_user_id, username, channel_id, created_at
+       FROM spam_hits ORDER BY id DESC LIMIT ? OFFSET ?`,
+    [limit, offset],
+  )
+}
+
 // User-lookup: match a Discord id exactly, or a username snapshot (target_tag)
 // by prefix, returning the most recently seen distinct targets. Powers the
 // dashboard search box (usernames drift, so we search historical snapshots too).
@@ -114,4 +178,11 @@ module.exports = {
   latestTag,
   linkedAccount,
   searchTargets,
+  // Phase 6b
+  memberCountsByWindow,
+  inviteJoinCountsByWindow,
+  tableCountsByWindow,
+  recentMemberEvents,
+  recentFilterHits,
+  recentSpamHits,
 }

server/src/model/moderation/moderation.model.js

@@ -7,9 +7,10 @@
 // without needing new columns on mod_actions.
 const moderationDb = require('./moderation.db')
 const botConfigDb = require('../botConfig/botConfig.db')
-const { zeroCounts, annotate, reshapeWindows } = require('./moderation.pure')
+const { zeroCounts, annotate, reshapeWindows, windowValue } = require('./moderation.pure')
 
 const DAY_MS = 24 * 60 * 60 * 1000
+const WINDOW_KEYS = ['24h', '7d', '30d']
 
 async function botApplicationId() {
   try {
@@ -20,15 +21,47 @@ async function botApplicationId() {
   }
 }
 
-// Counts by type across 24h / 7d / 30d windows for the overview tiles.
+// Counts by type across 24h / 7d / 30d windows for the overview tiles. Covers
+// moderation actions (mod_actions) plus the Phase 6b event streams: member
+// joins/leaves, attributed invite joins, and filter/spam hits.
 async function summary() {
   const now = Date.now()
-  const cutoff24h = new Date(now - DAY_MS)
-  const cutoff7d = new Date(now - 7 * DAY_MS)
-  const cutoff30d = new Date(now - 30 * DAY_MS)
+  const cutoffs = {
+    cutoff24h: new Date(now - DAY_MS),
+    cutoff7d: new Date(now - 7 * DAY_MS),
+    cutoff30d: new Date(now - 30 * DAY_MS),
+  }
 
-  const rows = await moderationDb.countsByWindow({ cutoff24h, cutoff7d, cutoff30d })
-  return reshapeWindows(rows)
+  const [modRows, memberRows, inviteRow, filterRow, spamRow] = await Promise.all([
+    moderationDb.countsByWindow(cutoffs),
+    moderationDb.memberCountsByWindow(cutoffs),
+    moderationDb.inviteJoinCountsByWindow(cutoffs),
+    moderationDb.tableCountsByWindow('filter_hits', cutoffs),
+    moderationDb.tableCountsByWindow('spam_hits', cutoffs),
+  ])
+
+  const windows = reshapeWindows(modRows).windows
+  const joinRow = memberRows.find((r) => r.event_type === 'join')
+  const leaveRow = memberRows.find((r) => r.event_type === 'leave')
+  for (const w of WINDOW_KEYS) {
+    windows[w].joins = windowValue(joinRow, w)
+    windows[w].leaves = windowValue(leaveRow, w)
+    windows[w].invite_joins = windowValue(inviteRow, w)
+    windows[w].filter_hits = windowValue(filterRow, w)
+    windows[w].spam_hits = windowValue(spamRow, w)
+  }
+  return { windows }
+}
+
+// Recent event feeds for the overview's secondary panel (Phase 6b).
+async function members(opts) {
+  return moderationDb.recentMemberEvents(opts)
+}
+async function filterHits(opts) {
+  return moderationDb.recentFilterHits(opts)
+}
+async function spamHits(opts) {
+  return moderationDb.recentSpamHits(opts)
 }
 
 async function recent(opts) {
@@ -69,4 +102,4 @@ async function search(term, opts) {
   return moderationDb.searchTargets(term, opts)
 }
 
-module.exports = { summary, recent, userActions, userSummary, search }
+module.exports = { summary, recent, userActions, userSummary, search, members, filterHits, spamHits }

server/src/model/moderation/moderation.pure.js

@@ -36,4 +36,12 @@ function reshapeWindows(rows) {
   return { windows }
 }
 
-module.exports = { zeroCounts, annotate, reshapeWindows }
+// Pull the count for one window key ('24h'|'7d'|'30d') out of a
+// { d1, d7, d30 } sum row, coercing to a number and tolerating a null row.
+function windowValue(row, key) {
+  if (!row) return 0
+  const col = key === '24h' ? row.d1 : key === '7d' ? row.d7 : row.d30
+  return Number(col) || 0
+}
+
+module.exports = { zeroCounts, annotate, reshapeWindows, windowValue }