rebrand: sweep remaining switchboard refs + rename cookies/storage keys

- CSS headers (4 files): Switchboard Core → Armature
- Editor .mjs headers (8 files): Chat Switchboard → Armature
- SQL migration comments + seed data (20 files): Switchboard Core → Armature
- Webhook header: X-Switchboard-Event → X-Armature-Event
- Cookie: sb_token → arm_token (3 Go files + auth.js)
- localStorage: sb_auth → arm_auth (auth.js + 2 test runners)
- localStorage: switchboard_theme → armature_theme (theme.js + base.html)
- Debug engine filter: chatSwitchboard/switchboard/sb_ → armatureChat/armature/arm_
- JS export: switchboardTheme → armatureTheme (theme.mjs + code-editor.mjs)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/middleware/auth.go

@@ -142,11 +142,11 @@ func parseAndValidateJWT(tokenString string, jwtSecret string) (*Claims, bool) {
 	return claims, true
 }
 
-// UserIDFromCookie extracts the user ID from the sb_token cookie without
+// UserIDFromCookie extracts the user ID from the arm_token cookie without
 // requiring authentication. Returns "" if no valid token is found.
 // Used by unauthenticated routes that want optional user context.
 func UserIDFromCookie(c *gin.Context, jwtSecret string) string {
-	cookie, err := c.Cookie("sb_token")
+	cookie, err := c.Cookie("arm_token")
 	if err != nil || cookie == "" {
 		return ""
 	}

server/middleware/page_auth.go

@@ -17,7 +17,7 @@ import (
 // Unlike Auth() which returns 401 JSON for API calls, this redirects
 // to the login page — appropriate for browser navigation.
 //
-// Token is read from the "sb_token" cookie (set by the login page JS)
+// Token is read from the "arm_token" cookie (set by the login page JS)
 // since page requests don't have Authorization headers.
 func AuthOrRedirect(cfg *config.Config, users store.UserStore, cache *UserStatusCache) gin.HandlerFunc {
 	loginPath := cfg.BasePath + "/login"
@@ -32,7 +32,7 @@ func AuthOrRedirect(cfg *config.Config, users store.UserStore, cache *UserStatus
 		// Try cookie first (set by login page), then Authorization header,
 		// then query param (for edge cases)
 		tokenString := ""
-		if cookie, err := c.Cookie("sb_token"); err == nil && cookie != "" {
+		if cookie, err := c.Cookie("arm_token"); err == nil && cookie != "" {
 			tokenString = cookie
 		}
 		if tokenString == "" {
@@ -109,7 +109,7 @@ func OptionalAuth(cfg *config.Config, users store.UserStore, cache *UserStatusCa
 		}
 
 		tokenString := ""
-		if cookie, err := c.Cookie("sb_token"); err == nil && cookie != "" {
+		if cookie, err := c.Cookie("arm_token"); err == nil && cookie != "" {
 			tokenString = cookie
 		}
 		if tokenString == "" {