setup: stop copying game discs into the project by default

setup_project.sh has always defaulted to STAGE_DISC=0 — probe the dump where
the user keeps it, write its absolute path into game.toml, and extract only
the small boot EXE into disc/. Two callers overrode that and copied instead:
NewProjectOptions.stage_disc defaulted True, and Project Studio's checkbox
was pre-ticked.

Staging copies every track into the repo, so a 3-disc PS1 set duplicates
~2.2 GB of a ROM library the user already owns and stores elsewhere — for no
gain, since disc/ is gitignored and a staged copy is never shipped either.

The checkbox is also relabelled "Stage disc" -> "Copy disc into project":
"stage" did not say what it costs. --stage-disc still works for anyone who
genuinely wants a self-contained tree. cli.py and setup_project.ps1 already
defaulted off and are unchanged.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0194TYJAqgyG9a9PJe9uUcgQ

tools/new_project_layout/project_studio/gui.py

@@ -451,7 +451,9 @@ class ProjectStudioApp:
         self.np_netplay_var = tk.BooleanVar(value=True)  # players default = 2
         self.np_ci_var = tk.BooleanVar(value=True)
         self.np_boxart_var = tk.BooleanVar(value=True)
-        self.np_stage_var = tk.BooleanVar(value=True)
+        # Off by default — see NewProjectOptions.stage_disc. The project reads
+        # the dump from where the user keeps it instead of duplicating it.
+        self.np_stage_var = tk.BooleanVar(value=False)
         self.np_generate_var = tk.BooleanVar(value=True)
         self.np_build_var = tk.BooleanVar(value=True)
         self.np_github_var = tk.BooleanVar(value=False)
@@ -910,7 +912,7 @@ class ProjectStudioApp:
             ("Netplay", self.np_netplay_var),
             ("CI", self.np_ci_var),
             ("Boxart", self.np_boxart_var),
-            ("Stage disc", self.np_stage_var),
+            ("Copy disc into project", self.np_stage_var),
             ("Generate", self.np_generate_var),
             ("Build", self.np_build_var),
             ("GitHub", self.np_github_var),

tools/new_project_layout/project_studio/newproject.py

@@ -40,7 +40,13 @@ class NewProjectOptions:
     lobby_url: str = "netplay.retcomm.net"
     enable_ci: bool = True
     fetch_boxart: bool = True
-    stage_disc: bool = True
+    # OFF, matching setup_project.sh's own STAGE_DISC=0 default: the project
+    # references the dump where the user already keeps it (game.toml gets the
+    # absolute --disc path) and only the small boot EXE is written into disc/.
+    # Staging copies every track into the repo, so a 3-disc PS1 set duplicates
+    # ~2 GB of the user's ROM library per project. Opt in with --stage-disc
+    # when a self-contained tree is actually wanted.
+    stage_disc: bool = False
     do_generate: bool = True
     do_build: bool = True
     create_github: bool = False