Re-audit round 4: 5 blind reviewers over the new surface — 24 fixes, +28 tests

The findings clustered exactly where prediction said: the unreviewed web
layer. The big ones: decisions made while an extract/resolve job runs
are now refused with a 409 (the job's end-of-run rewrite from a
start-of-run snapshot would silently revert them); a cross-origin guard
blocks preflight-free mutations from hostile webpages (bodyless run
triggers, cross-site photo form posts); the JobRunner sets terminal
status in a finally catching BaseException (a greenlet death could
wedge every future run behind 409s) and writes tracebacks into the
visible job log; and a boot token lets clients accept the revision
reset after a server restart instead of freezing forever.

Even the thrice-audited core yielded one HIGH: an unvetoed bare
typo-read sibling of a confident row duplicated its add when the game
wasn't in the collection — diff now treats it as satisfied. Second-copy
adds carry a flag through to_add.csv and the upload log so verify
honestly reports them unverifiable instead of OK. Also: merged_into
chains collapse transitively; diff/enrich treat a BGG queue timeout
like a missing token; enrich prunes orphaned games.json keys; the
wizard shell-quotes .env values and creates the file 0600 from the
first byte; fsio stats the tmp inode before replace and uses unique tmp
names; an explicit missing --config errors; storage state is
owner-only; extract re-extracts corrupt caches, aborts on 3 identical
failures, and exits nonzero when nothing succeeded; torn JSON artifacts
degrade with in-browser warnings instead of 500ing every page; photo
uploads are atomic with cache-invalidation ordered first; the pipeline
page computes `running` before the buttons that depend on it; the
photo dropzone alerts on network failure; and lost-contact banners
clear on recovery everywhere.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_config.py

@@ -8,8 +8,11 @@ from bggpipe.config import Config, load_config
 
 
 def test_defaults_when_no_file(tmp_path, monkeypatch):
+    # no config.toml in cwd and no explicit path -> defaults (an EXPLICIT
+    # missing path errors instead; see the dedicated test)
     monkeypatch.delenv("BGG_USERNAME", raising=False)
-    cfg = load_config(tmp_path / "missing.toml")
+    monkeypatch.chdir(tmp_path)
+    cfg = load_config()
     assert cfg == Config()
     assert cfg.cache_dir == Path("data/bgg_cache")
 
@@ -44,3 +47,10 @@ def test_unknown_toml_keys_warn(tmp_path, monkeypatch):
     p.write_text('photo_dir = "oops"\n')
     with pytest.warns(UserWarning, match="photo_dir"):
         load_config(p)
+
+
+def test_explicit_missing_config_errors_instead_of_silent_defaults(tmp_path):
+    import pytest
+
+    with pytest.raises(FileNotFoundError, match="does not exist"):
+        load_config(tmp_path / "nope.toml")