refactor(brand): rename F∆I -> Ch∆In + hub binary fai -> chain

Studio follows the platform rename: product branding F∆I -> Ch∆In in UI
strings, command examples fai -> chain, and — critically — the spawned
hub binary path ~/.fai/bin/fai -> ~/.fai/bin/chain so Studio launches
the renamed binary. The fai_* Dart identifiers (FaiLog, widget files,
the generated SDK) stay = vendor/internal namespace. flutter analyze:
no issues.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_localizations.dart

@@ -101,7 +101,7 @@ abstract class AppLocalizations {
   /// App-bar title in the OS task switcher.
   ///
   /// In en, this message translates to:
-  /// **'F∆I Studio'**
+  /// **'Ch∆In Studio'**
   String get appTitle;
 
   /// No description provided for @navWelcome.
@@ -113,7 +113,7 @@ abstract class AppLocalizations {
   /// No description provided for @welcomeHeroTitle.
   ///
   /// In en, this message translates to:
-  /// **'F∆I Platform'**
+  /// **'Ch∆In Platform'**
   String get welcomeHeroTitle;
 
   /// No description provided for @welcomeHeroSubtitle.
@@ -419,7 +419,7 @@ abstract class AppLocalizations {
   /// No description provided for @welcomeChecklistModuleHint.
   ///
   /// In en, this message translates to:
-  /// **'Install a module from the Store — pick whichever category fits your work. Modules are sandboxed F∆I components.'**
+  /// **'Install a module from the Store — pick whichever category fits your work. Modules are sandboxed Ch∆In components.'**
   String get welcomeChecklistModuleHint;
 
   /// No description provided for @welcomeChecklistFlow.
@@ -1445,7 +1445,7 @@ abstract class AppLocalizations {
   /// No description provided for @storeTodayDeck.
   ///
   /// In en, this message translates to:
-  /// **'From the F∆I editor'**
+  /// **'From the Ch∆In editor'**
   String get storeTodayDeck;
 
   /// No description provided for @storeTodayDismissTooltip.
@@ -1991,7 +1991,7 @@ abstract class AppLocalizations {
   /// No description provided for @modulesNoneHint.
   ///
   /// In en, this message translates to:
-  /// **'Run `fai install <capability-name>` or check ~/.fai/modules/.'**
+  /// **'Run `chain install <capability-name>` or check ~/.fai/modules/.'**
   String get modulesNoneHint;
 
   /// No description provided for @modulesReloadTooltip.
@@ -2105,7 +2105,7 @@ abstract class AppLocalizations {
   /// No description provided for @flowsNoneHint.
   ///
   /// In en, this message translates to:
-  /// **'Save a flow with `fai admin flows save <name> <flow.yaml>` and it shows up here.'**
+  /// **'Save a flow with `chain admin flows save <name> <flow.yaml>` and it shows up here.'**
   String get flowsNoneHint;
 
   /// No description provided for @flowsRunDialogTitle.
@@ -2615,7 +2615,7 @@ abstract class AppLocalizations {
   /// No description provided for @welcomeChecklistNextModuleBody.
   ///
   /// In en, this message translates to:
-  /// **'Generate a Rust+WASM scaffold with `fai new module <name>`. The module-sdk handles the WIT plumbing; you write a typed invoke.'**
+  /// **'Generate a Rust+WASM scaffold with `chain new module <name>`. The module-sdk handles the WIT plumbing; you write a typed invoke.'**
   String get welcomeChecklistNextModuleBody;
 
   /// No description provided for @welcomeChecklistNextModuleButton.
@@ -2831,7 +2831,7 @@ abstract class AppLocalizations {
   /// No description provided for @errUnavailableHint.
   ///
   /// In en, this message translates to:
-  /// **'Make sure `fai serve` (or `fai daemon start`) is running and the daemon endpoint matches Studio\'s settings.'**
+  /// **'Make sure `chain serve` (or `chain daemon start`) is running and the daemon endpoint matches Studio\'s settings.'**
   String get errUnavailableHint;
 
   /// No description provided for @errUnauthenticated.
@@ -3305,7 +3305,7 @@ abstract class AppLocalizations {
   /// No description provided for @doctorDaemonControlHint.
   ///
   /// In en, this message translates to:
-  /// **'Studio shells out to the platform binary — mirrors `fai daemon …` exactly so the CLI and UI stay in lockstep.'**
+  /// **'Studio shells out to the platform binary — mirrors `chain daemon …` exactly so the CLI and UI stay in lockstep.'**
   String get doctorDaemonControlHint;
 
   /// No description provided for @doctorDaemonControlWorking.
@@ -3353,7 +3353,7 @@ abstract class AppLocalizations {
   /// No description provided for @doctorPathsEmpty.
   ///
   /// In en, this message translates to:
-  /// **'Daemon did not report file paths. Update the running hub via `fai daemon restart`.'**
+  /// **'Daemon did not report file paths. Update the running hub via `chain daemon restart`.'**
   String get doctorPathsEmpty;
 
   /// No description provided for @doctorOpenError.
@@ -3371,7 +3371,7 @@ abstract class AppLocalizations {
   /// No description provided for @doctorUpdateBody.
   ///
   /// In en, this message translates to:
-  /// **'Channel {channel} now offers {version}. Apply via the button — Studio shells out to `fai update apply --channel {channel}`.'**
+  /// **'Channel {channel} now offers {version}. Apply via the button — Studio shells out to `chain update apply --channel {channel}`.'**
   String doctorUpdateBody(String channel, String version);
 
   /// No description provided for @doctorUpdateUnreachable.
@@ -3467,7 +3467,7 @@ abstract class AppLocalizations {
   /// No description provided for @hubUnreachableHint.
   ///
   /// In en, this message translates to:
-  /// **'Start the hub with `fai serve`.'**
+  /// **'Start the hub with `chain serve`.'**
   String get hubUnreachableHint;
 
   /// No description provided for @languageEnglish.
@@ -4253,13 +4253,13 @@ abstract class AppLocalizations {
   /// No description provided for @addSourceHowItWorksBody.
   ///
   /// In en, this message translates to:
-  /// **'A module is a directory with a module.yaml + the WASM artifact. To share it: pack it (`fai pack <dir>`) and host the resulting `.fai` bundle anywhere (your own Forgejo / GitHub / S3). The hub installs by URL and verifies the signature against its trust store.\n\nDeveloping locally? Use the CLI — Studio cannot install from an unpacked directory (yet):'**
+  /// **'A module is a directory with a module.yaml + the WASM artifact. To share it: pack it (`chain pack <dir>`) and host the resulting `.fai` bundle anywhere (your own Forgejo / GitHub / S3). The hub installs by URL and verifies the signature against its trust store.\n\nDeveloping locally? Use the CLI — Studio cannot install from an unpacked directory (yet):'**
   String get addSourceHowItWorksBody;
 
   /// No description provided for @addSourceCliExample.
   ///
   /// In en, this message translates to:
-  /// **'fai install --link /path/to/module'**
+  /// **'chain install --link /path/to/module'**
   String get addSourceCliExample;
 
   /// No description provided for @addSourceInstallButton.
@@ -4337,7 +4337,7 @@ abstract class AppLocalizations {
   /// No description provided for @faiBinaryNotFoundHint.
   ///
   /// In en, this message translates to:
-  /// **'Install the F∆I platform, or point Studio at an existing `fai` binary.'**
+  /// **'Install the Ch∆In platform, or point Studio at an existing `fai` binary.'**
   String get faiBinaryNotFoundHint;
 
   /// No description provided for @faiBinaryLocateButton.