Resolve giant condor wrapper from the active venv, not a hardcoded path

write_submit baked in cfg.repo_dir/.venv/bin/giant unconditionally, which
breaks when submitting from a differently-named or non-default venv (e.g.
--extra cuda). Prefer the giant executable next to sys.executable (the venv
actually running the submit), falling back to repo_dir/.venv/bin/giant.

giant/analysis/condor.py

@@ -43,6 +43,7 @@ from __future__ import annotations
 
 import json
 import shutil
+import sys
 from dataclasses import dataclass, field
 from pathlib import Path
 
@@ -356,7 +357,7 @@ class SubmitConfig:
 _WRAPPER = """#!/bin/bash
 set -euo pipefail
 cd {repo_dir}
-exec {repo_dir}/.venv/bin/giant analyze compute-one --id "$1" --chunk "$2" --run-dir {run_dir}
+exec {giant_exe} analyze compute-one --id "$1" --chunk "$2" --run-dir {run_dir}
 """
 
 
@@ -405,6 +406,29 @@ def _job_walltimes(
     return jobs
 
 
+def _resolve_giant_executable(repo_dir: Path) -> Path:
+    """Path to the ``giant`` entry point to bake into the condor wrapper script.
+
+    Prefers the venv currently running this process (``sys.executable``'s
+    sibling ``giant``) so a submit from a non-default venv (e.g. ``--extra
+    cuda`` on a dev box) doesn't silently pick up a different one; falls back
+    to ``repo_dir/.venv/bin/giant`` for the case this is invoked from outside
+    any venv (e.g. a system Python).
+    """
+    active = Path(sys.executable).parent / "giant"
+    if active.exists():
+        return active
+    venv_giant = repo_dir / ".venv" / "bin" / "giant"
+    if not venv_giant.exists():
+        raise FileNotFoundError(
+            f"no `giant` executable found next to {sys.executable} or at "
+            f"{venv_giant} — condor jobs run it directly (no `uv` on the "
+            f"worker image), so run `uv sync --extra cpu` in {repo_dir} "
+            "before submitting."
+        )
+    return venv_giant
+
+
 def write_submit(cfg: SubmitConfig, ids: list[str] | None = None) -> Path:
     """Write the wrapper script, (plot, chunk) job list, and HTCondor submit
     description.
@@ -422,13 +446,7 @@ def write_submit(cfg: SubmitConfig, ids: list[str] | None = None) -> Path:
     independent values — checked equal up front so a mismatch is a clear error
     here rather than an ``IndexError`` out of ``_job_walltimes``.
     """
-    venv_giant = cfg.repo_dir / ".venv" / "bin" / "giant"
-    if not venv_giant.exists():
-        raise FileNotFoundError(
-            f"{venv_giant} not found — condor jobs run it directly (no `uv` on "
-            f"the worker image), so run `uv sync --extra cpu` in {cfg.repo_dir} "
-            "before submitting."
-        )
+    giant_exe = _resolve_giant_executable(cfg.repo_dir)
 
     ids = ids or catalog_ids()
     run_dir = cfg.run_dir
@@ -446,7 +464,9 @@ def write_submit(cfg: SubmitConfig, ids: list[str] | None = None) -> Path:
     (run_dir / "reduced_partial").mkdir(parents=True, exist_ok=True)
 
     wrapper = run_dir / "run_compute.sh"
-    wrapper.write_text(_WRAPPER.format(repo_dir=cfg.repo_dir, run_dir=run_dir))
+    wrapper.write_text(
+        _WRAPPER.format(repo_dir=cfg.repo_dir, giant_exe=giant_exe, run_dir=run_dir)
+    )
     wrapper.chmod(0o755)
 
     jobs = _job_walltimes(run_dir, ids, cfg.n_chunks)