Migrate CI from Taskfile to Dagger

- Add Dagger to flake.nix
- Create Dagger module in ci/ with Flutter build/test logic
- Update .forgejo/workflows/ci.yml to use Dagger
- Move Android emulator tests to separate disabled workflow
- Add .daggerignore to exclude host junk

flake.lock

@@ -1,5 +1,25 @@
 {
   "nodes": {
+    "dagger": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1778107833,
+        "narHash": "sha256-q5XQep2mpgTPiWwuYB1+L2dsFeACT6sHx8J939iM+HE=",
+        "owner": "dagger",
+        "repo": "nix",
+        "rev": "873cc22ba46b73d4a6c1aa6c102ef3aabc736496",
+        "type": "github"
+      },
+      "original": {
+        "owner": "dagger",
+        "repo": "nix",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -20,11 +40,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1778430510,
-        "narHash": "sha256-Ti+ZBvW6yrWWAg2szExVTwCd4qOJ3KlVr1tFHfyfi8Q=",
+        "lastModified": 1778737229,
+        "narHash": "sha256-6xWoytx8jFW4PF1GjRm/i/53trbpKGfz6zjzQGBr4cI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8fd9daa3db09ced9700431c5b7ad0e8ba199b575",
+        "rev": "d7a713c0b7e47c908258e71cba7a2d77cc8d71d5",
         "type": "github"
       },
       "original": {
@@ -36,6 +56,7 @@
     },
     "root": {
       "inputs": {
+        "dagger": "dagger",
         "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }