feat(bench): automate B7 shader profiles, wire B12b trials, settle 45s

- gen_shader_profiles.py + shader-profiles/: Iris per-pack option files
  resolved from each pack's profile.* lines (Iris has no profile key)
- bench.py: flag rows shader_not_loaded when Iris falls back to vanilla
  rendering (analyze.py treats it as invalid)
- matrix: shader_options session key, trial jar globs pinned to the
  downloaded Modrinth builds, post-join settle 45 s (B0 v1 showed rep 1
  still warming at 10 s)

analysis/client-perf/harness/tests/test_matrix.py

@@ -238,7 +238,69 @@ class Commands(Fixture):
 
     def test_seconds(self):
         b3 = matrix.expand(self.m, matrix.block_map(self.m)["B3"])
-        self.assertEqual(matrix.session_seconds(b3[0], 60), 60 + 3 * 45 + 3 * 130)
+        self.assertEqual(matrix.session_seconds(b3[0], 60), 60 + 10 + 3 * 45 + 3 * 130)
+
+
+class ShaderOptions(Fixture):
+    def b7(self, **extra):
+        d = tomllib.loads(MINI.format(tmp=self.tmp))
+        sess = {"variant": "C1", "plan": "s1,s4", "shader": "Pack.zip",
+                "shader_profile": "low", "tag": "p-low", **extra}
+        d["block"].append({"id": "B7", "rule": "shaders", "sessions": [sess]})
+        return d
+
+    def test_emitted(self):
+        f = self.tmp / "Pack.low.txt"
+        f.write_text("A=1\n")
+        d = self.b7(shader_options=str(f))
+        self.assertEqual(matrix.validate(d, self.out), [])
+        s = matrix.expand(d, matrix.block_map(d)["B7"])[0]
+        argv, miss = matrix.bench_argv(d, s)
+        self.assertEqual(miss, [])
+        self.assertEqual(argv[argv.index("--shader") + 1], "Pack.zip")
+        self.assertEqual(argv[argv.index("--shader-options") + 1], str(f))
+        self.assertIn("--shader-options", matrix.BENCH_SESSION_FLAGS)
+
+    def test_missing_file_and_relative_path(self):
+        d = self.b7(shader_options="shader-profiles/does-not-exist.txt")
+        s = matrix.expand(d, matrix.block_map(d)["B7"])[0]
+        argv, miss = matrix.bench_argv(d, s)
+        self.assertEqual(argv[argv.index("--shader-options") + 1],
+                         str(matrix.HERE / "shader-profiles/does-not-exist.txt"))
+        self.assertTrue(any("shader options" in x for x in miss))
+
+    def test_needs_shader(self):
+        d = self.b7(shader_options="x.txt", shader="off")
+        self.assertIn("shader_options needs shader", "\n".join(matrix.validate(d, self.out)))
+
+    def test_spec_hash_tracks_file_content(self):
+        f = self.tmp / "Pack.low.txt"
+        f.write_text("A=1\n")
+        d = self.b7(shader_options=str(f))
+        s = matrix.expand(d, matrix.block_map(d)["B7"])[0]
+        argv, _ = matrix.bench_argv(d, s)
+        h1 = matrix.spec_hash(argv, s)
+        f.write_text("A=2\n")
+        self.assertNotEqual(h1, matrix.spec_hash(argv, s))
+        # sessions without shader_options keep the original hash formula (resume state)
+        b0 = matrix.expand(self.m, matrix.block_map(self.m)["B0"])[0]
+        a0, _ = matrix.bench_argv(self.m, b0)
+        blob = json.dumps({"argv": a0, "manual": False}, sort_keys=True)
+        import hashlib
+        self.assertEqual(matrix.spec_hash(a0, b0),
+                         hashlib.sha256(blob.encode()).hexdigest()[:16])
+
+    def test_real_b7_automated(self):
+        m = matrix.load()
+        rows = matrix.expand(m, matrix.block_map(m)["B7"])
+        shaded = [s for s in rows if s["shader"] != "off"]
+        self.assertEqual(len(shaded), 4)
+        for s in rows:
+            self.assertFalse(s.get("manual"), s["label"])
+        for s in shaded:
+            argv, miss = matrix.bench_argv(m, s)
+            self.assertEqual([x for x in miss if "shader options" in x], [], s["label"])
+            self.assertTrue(Path(argv[argv.index("--shader-options") + 1]).is_file())
 
 
 class Resume(Fixture):