feat: add mind model with versioned personality, templates and self-model

Phase 2. Minds are rows with a slug, status (active/disabled/archived),
cognitive configuration and a pointer to the current personality version.
Personalities are structured (identity, values, traits, communication,
behaviour, free text) with a deterministic Brief() used by prompts and the
editor preview. Every change appends a personality_versions row protected
by the append-only trigger; restore copies an old version forward.
Templates carry reusable personalities; minds record their overrides so a
template can be re-applied without losing mind-specific edits. The
self-model starts with structural limitations the mind cannot drop
(no policy changes, no influence over shutdown, no cross-mind access).

API, UI (list, overview, editor with sliders/diff/history/import/export,
template editor) and noemactl mind/template commands. All mutations are
audited with field-level diffs.

cmd/noemactl/main.go

@@ -40,6 +40,9 @@ type command struct {
 
 var commands []command
 
+// extraCommands are registered by other files in this package via init.
+var extraCommands []command
+
 func main() {
 	commands = []command{
 		{"status", "show daemon status", cmdStatus},
@@ -47,6 +50,7 @@ func main() {
 		{"user", "create <username> [-role r] – manage users (offline)", cmdUser},
 		{"version", "print version", func([]string) int { fmt.Println(version.Version); return exitOK }},
 	}
+	commands = append(commands, extraCommands...)
 	if len(os.Args) < 2 || os.Args[1] == "-h" || os.Args[1] == "--help" || os.Args[1] == "help" {
 		usage()
 		os.Exit(exitUsage)