test(pipeline): the checks of the pure pipeline

Stream, Normalize, Merge, Dispositions, Config, CodeKeys and the pure half
of CommitsMode, each a test of its own (131 checks). The fixture rewrites
are checked in (code-keys/<name>/, commits3/), so the suite reads fixtures
and edits nothing. The allowlist, command-line and MCP checks of
CommitsMode come with the pool they test.

Among them: this binary's `<exe> sql` spelling counts as a SQL call, and a
result line with a raw U+2028 in a JSON string is still the result line.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Goldens/fixture/commits3/0001-add-the-greeting-module.patch

@@ -0,0 +1,30 @@
+From 1111111111111111111111111111111111111111 Mon Sep 17 00:00:00 2001
+From: Jorijn van der Graaf <jorijnvdgraaf@catcrafts.net>
+Date: Wed, 24 Sep 2026 10:00:00 +0200
+Subject: [PATCH 1/3] add the greeting module
+
+---
+ hello.py | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+ create mode 100644 hello.py
+
+diff --git a/hello.py b/hello.py
+new file mode 100644
+index 0000000..a1b2c3d
+--- /dev/null
++++ b/hello.py
+@@ -0,0 +1,9 @@
++"""Greetings."""
++
++
++def greet():
++    return "hello"
++
++
++def farewell():
++    return "bye"
+
+base-commit: 0000000000000000000000000000000000000000
+-- 
+2.51.0
+