test: deterministic operator-guide screenshot harness

integration_test/guide_shots_test.dart boots a hermetic hub
(HubFixture), seeds demo projects (open Bürgeramt; sealed
Ratsinformation and a setup.applied audit event only when the
runner confirms an isolated $HOME), launches the app in German +
dark mode, walks every sidebar page in Cmd order with
content-aware waits, opens the workspace switcher and the setup
wizard, and writes the guide PNGs via a driverless RepaintBoundary
capture. Driven by the platform repo's scripts/regen-studio-guide.sh.

Also fixes the hub fixture's binary resolution, dead since the
rename (it looked for 'fai' and ../chain_platform/): now $CHAIN_BIN,
'chain' on PATH, then ../fai_chain/target/{release,debug}/chain —
the integration tests actually run again instead of silently
skipping.

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

pubspec.lock

@@ -172,6 +172,11 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.3.5"
+  flutter_driver:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_highlight:
     dependency: transitive
     description:
@@ -219,6 +224,11 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  fuchsia_remote_debug_protocol:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   google_cloud:
     dependency: transitive
     description:
@@ -291,6 +301,11 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.1.2"
+  integration_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   intl:
     dependency: "direct main"
     description:
@@ -435,6 +450,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      sha256: c6248e4526673988586e8c00bb22a49210c258dc91df5227d5da9748ecf79744
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.0.5"
   protobuf:
     dependency: transitive
     description:
@@ -544,6 +567,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.4.1"
+  sync_http:
+    dependency: transitive
+    description:
+      name: sync_http
+      sha256: "7f0cd72eca000d2e026bcd6f990b81d0ca06022ef4e32fb257b30d3d1014a961"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.3.1"
   term_glyph:
     dependency: transitive
     description:
@@ -664,6 +695,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.1"
+  webdriver:
+    dependency: transitive
+    description:
+      name: webdriver
+      sha256: "2f3a14ca026957870cfd9c635b83507e0e51d8091568e90129fbf805aba7cade"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.1.0"
   win32:
     dependency: transitive
     description: