build: update dependencies and SDK constraints

Update characters, collection, and meta packages to their latest versions.
Bump minimum Dart SDK version to 3.7.0 and Flutter to 3.27.0.

pubspec.lock

@@ -45,10 +45,10 @@ packages:
     dependency: transitive
     description:
       name: characters
-      sha256: "04a925763edad70e8443c99234dc3328f442e811f1d8fd1a72f1c8ad0f69a605"
+      sha256: f71061c654a3380576a52b451dd5532377954cf9dbd272a78fc8479606670803
       url: "https://pub.dev"
     source: hosted
-    version: "1.3.0"
+    version: "1.4.0"
   checked_yaml:
     dependency: transitive
     description:
@@ -77,10 +77,10 @@ packages:
     dependency: transitive
     description:
       name: collection
-      sha256: a1ace0a119f20aabc852d165077c036cd864315bd99b7eaa10a60100341941bf
+      sha256: "2f5709ae4d3d59dd8f7cd309b4e023046b57d8a6c82130785d2b0e5868084e76"
       url: "https://pub.dev"
     source: hosted
-    version: "1.19.0"
+    version: "1.19.1"
   cookie_jar:
     dependency: transitive
     description:
@@ -271,10 +271,10 @@ packages:
     dependency: transitive
     description:
       name: meta
-      sha256: bdb68674043280c3428e9ec998512fb681678676b3c54e773629ffe74419f8c7
+      sha256: e3641ec5d63ebf0d9b41bd43201a66e3fc79a65db5f61fc181f04cd27aab950c
       url: "https://pub.dev"
     source: hosted
-    version: "1.15.0"
+    version: "1.16.0"
   package_info_plus:
     dependency: transitive
     description:
@@ -625,5 +625,5 @@ packages:
     source: hosted
     version: "3.1.3"
 sdks:
-  dart: ">=3.6.0 <4.0.0"
+  dart: ">=3.7.0-0 <4.0.0"
   flutter: ">=3.27.0"