feat(FN-1163): align command references with fn naming

- Update CLI command strings, help text, and project-resolution messaging to reference fn
- Sync core backup/store messaging and dashboard API/planning/subtask prompt examples with fn usage
- Refresh dashboard UI copy in settings, project detection, and PR guidance for consistent command naming
- Adjust CLI/dashboard tests and add a @gsxdsm/fusion changeset for the naming alignment patch

packages/cli/src/bin.ts

@@ -59,7 +59,7 @@ const HELP = `
 fn — AI-orchestrated task board
 
 Usage:
-  fn init [opts]                      Initialize a new kb project in the current directory
+  fn init [opts]                      Initialize a new fn project in the current directory
   fn dashboard                        Start the board web UI
   fn dashboard --paused               Start with automation paused
   fn dashboard --dev                  Start web UI only (no AI engine)