Global code ovehaul - remove CAS and other, add 15 minute greet check

- Remove CAS, as it no longer works for us
- Remove other checks
- Implement 15 minute greet timeout check
- Fix chat logos
- Ditch thirdparty logger, use stdlib log facility wrapper for logging

internal/elog/globals.go

@@ -0,0 +1,59 @@
+package elog
+
+import (
+	"errors"
+	"sync"
+	"time"
+)
+
+const (
+	// chatLockIdleTimeout is how long a chat's lock entry may sit unused before it
+	// is evicted. Without it the registry grows by one entry per chat ever seen.
+	chatLockIdleTimeout = time.Hour
+
+	// stampLayout is the per-line timestamp. GMT+0 with millisecond precision.
+	stampLayout = "15:04:05.000"
+
+	// logFilePerm is the mode for a newly created chat log file.
+	logFilePerm = 0o644
+
+	// logDirPerm is the mode for the chat, year and month directories.
+	//
+	// It is deliberately not logFilePerm. A directory needs the execute bit to
+	// be traversable, and 0o644 has none, so creating the tree with the file mode
+	// makes every subsequent open inside it fail with EACCES rather than ENOENT
+	// — a failure reportFailure would swallow, leaving chat logging to silently
+	// produce no files at all.
+	//
+	// The two live in one block on purpose: they are a pair that must never be
+	// confused with each other, and keeping them adjacent is what makes confusing
+	// them hard. They are here, in globals.go, because that is where every
+	// package-level const belongs — the pair argument was weighed against rule 2
+	// and rule 2 won, once, on the record.
+	logDirPerm = 0o755
+)
+
+var (
+	// errNotDirectory marks a chat_logs path that exists but is a regular file.
+	errNotDirectory = errors.New("chat_logs path is not a directory")
+
+	// root is the configured chat-logs directory. Empty means chat logging is
+	// disabled and every Log* call is a no-op.
+	root string
+
+	// failing records that a write error has been reported and not yet cleared,
+	// so a persistent failure (a full disk) logs once instead of once per event.
+	failing bool
+
+	// stateMu guards root and failing.
+	stateMu sync.RWMutex
+
+	// registryMu guards locks. It is never held while a chat lock is acquired,
+	// or the whole logger would serialise.
+	registryMu sync.Mutex
+
+	// locks is the per-chat lock registry.
+	locks = map[int64]*chatLock{}
+)
+
+/* vim: set ft=go noet ai ts=4 sw=4 sts=4: */