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.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 }