Refactor webhook to use Redis queue with NotificationQueue class

Architecture Changes:
- Add NotificationQueue class (src/NotificationQueue.php) as producer-side counterpart
  to teams-chat-bot's Redis queue. Enqueues JSON envelopes with message text, room,
  dedup_key, and full GitHub payload. Falls back to direct Power Automate POST if Redis
  is unavailable so events are never silently dropped.
- Add GithubMessageBuilder class (src/GithubMessageBuilder.php) extracting all message
  formatting logic from github.php into a dedicated, testable class with build() method
  returning ['avatar' => ..., 'alias?' => ..., 'text' => ...].
- Refactor web/github.php to use the new classes instead of inline message building
  and direct curl calls to RocketChat/Teams. Now validates, picks room, builds dedup key,
  rate-limits optionally, formats message via GithubMessageBuilder, and enqueues via
  NotificationQueue.
- Remove inline SendToChat(), WildCard(), and full switch-case event handlers from github.php.
  These are replaced by GithubMessageBuilder buildText() method which handles: issues,
  pull_request, push, check_suite/check_run, workflow_run/workflow_job, gollum, and default.

New Dependencies (composer.json):
- predis/predis ^2.0 — Redis client for NotificationQueue
- vlucas/phpdotenv ^5.5 — Environment variable loading from .env
- Add autoload classmap for src/ directory

Environment Configuration (.env.dist):
- GITHUB_WEBHOOKS_SECRET — HMAC secret for webhook validation
- NOTIF_QUEUE_ENABLED=true — Enable Redis queue (default), fall back to direct POST when false
- NOTIF_QUEUE_KEY_PREFIX=notif: — Redis key prefix
- REDIS_HOST=dragonfly.mailbaby.net, REDIS_PORT=6379 — Redis connection (fallback)
- LOG_LEVEL=debug — Disk log verbosity (debug/info/warn)
- RATE_LIMIT_WINDOW=0 — Producer-side rate limiter window in seconds (0=disabled, recommended)

NotificationQueue Features:
- Envelope v1 format with uuid, ts, expires_at, room, type, message, card, extra, fallback_webhook_url
- MAX_BYTES=262144 (256KB) — strips raw payload first if oversized, then truncates message
- TTL_SECONDS=300 — envelope expiration
- Per-event dedup keys: github:push:{repo}:{branch}, github:issue:{repo}:{num}, etc.
- shouldSendOrSuppress() — SET/GET-based rate limiter using Redis SETEX with NX flag
- Dispositions: queued, direct_flag_off, direct_no_redis, direct_redis_exception, direct_oversize, failed_no_fallback

Room Routing:
- int-dev-announce: sugarcraft/* repos + detain/{CandyCore,scoop-emulators,detain,sugarcraft,watchable,php-dup-finder}
- notifications: all other repos

Deduplication Keys per event type:
- push: github:push:{repo}:{branch}
- issues: github:issue:{repo}:{number}
- pull_request: github:pr:{repo}:{number}
- check_run: github:checkrun:{repo}:{sha7}
- check_suite: github:check:{repo}:{sha7}
- workflow_run: github:wf:{repo}:{branch}:{name}
- workflow_job: github:wfjob:{repo}:{branch}:{jobName}
- gollum: github:wiki:{repo}
- status: github:status:{repo}:{sha7}
- star/watch/fork: github:{event}:{repo}
- ping: github:ping:{repo}

Logging:
- GITHUB_LOG_DIR = log/ — daily subdirectories (Y/m/d/)
- github_log_event() function for debug-level disk logging
- error_log for disposition reporting: github: disp={queued|direct_...} {event}({action}) repo={repo} room={room} dedup={key} text="..."

README Updated:
- Complete architecture diagram with flow
- Configuration reference for all .env variables
- RocketChat/Teams channel URL table
- Event handling flow description
- Supported events table with emoji and description
- Message format features (markdown links, branch backticks, labels, truncation)
- Events ignored by design table
- NotificationQueue envelope format and delivery flow
- Deduplication key formats table
- Dispositions table
- Logging directory structure
- GithubWebhook and GithubMessageBuilder API reference
- Test fixtures listing (46 event types)
- Quality tools and dependencies

Author: detain

.env.dist

@@ -0,0 +1,29 @@
+# GitHub webhook HMAC secret — must match the secret configured in
+# https://github.com/organizations/interserver/settings/hooks
+GITHUB_WEBHOOKS_SECRET=
+
+# Notification queue settings — when NOTIF_QUEUE_ENABLED=true the github
+# webhook pushes envelopes onto Redis for the teams-chat-bot to consume.
+# When false (default), it falls through to direct Power Automate POSTs.
+NOTIF_QUEUE_ENABLED=true
+NOTIF_QUEUE_KEY_PREFIX=notif:
+
+# Redis / Dragonfly connection (used by NotificationQueue when enabled).
+# These are only consulted as a fallback — the canonical values come from
+# /home/sites/mystage/include/config/config.settings.php which src/config.php
+# loads automatically. Override here only when running outside the shared
+# InterServer environment.
+REDIS_HOST=dragonfly.mailbaby.net
+REDIS_PORT=6379
+
+# Disk log verbosity for incoming events:
+#   debug → write every event
+#   info  → write only on send-failure (recommended)
+#   warn  → don't write at all
+LOG_LEVEL=debug
+
+# Producer-side per-event-type rate limiter window (seconds). 0 disables
+# (default) — recommended, since the teams-chat-bot already coalesces and
+# edits-on-followup downstream. Only set non-zero to suppress same-dedup_key
+# bursts at the webhook itself.
+RATE_LIMIT_WINDOW=0

.gitignore

@@ -1,3 +1,4 @@
+.env
 vendor/
 src/config.php
 composer.lock