fix(ci): exclude fvm/ and other large dirs from Dagger source sync

The source sync (Directory.Sync in selectFunc) was uploading ~7.4 GB /
78k files to the remote engine, blocking dagger call for 16+ minutes.

Root cause: .daggerignore had '.fvm/' but the actual directory is 'fvm/'
(no leading dot), so the 1.9 GB Flutter SDK cache was always uploaded.
Also missing: go/ pkg cache (309 MB), .claude/ session files, agent logs.

goroutine dump confirmed the hang in directoryValue.Get → Directory.Sync
→ HTTP/2 roundTrip waiting on the engine — not gRPC teardown as suspected.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.daggerignore

@@ -6,7 +6,9 @@
 
 # Build artifacts and tools
 build/
+go/
 .dart_tool/
+fvm/
 .fvm/
 .pub-cache/
 .dart-cli-completion/
@@ -48,3 +50,7 @@ snap/
 .forgejo
 .fvmrc
 .envrc
+
+# AI / tooling session data
+.claude/
+.sharedinbox-agent-logs/