migrate-kf6-seds: add 600s timeout on per-recipe cook (C-7)

Several KF6 recipes (kf6-kauth, kf6-kconfig, kf6-kwidgetsaddons)
use autotools and their `autoreconf` step can take 5+ minutes
on a clean cook. Without a per-recipe timeout, a hung cook
blocks the migration script indefinitely and leaves
`source-pristine/` snapshots lingering on disk.

The sed chain we care about runs in the recipe's [build].script
BEFORE the configure step, so a 10-minute window is plenty.
The snapshot at step 2 is already on disk, so even if the
cook is killed by the timeout, the post-cook source state
is still useful for the diff.

Adds test_cook_has_timeout regression test (123 Python tests
total). All 7 test files pass.

local/scripts/migrate-kf6-seds-to-patches.sh

@@ -166,7 +166,17 @@ for recipe_dir in "${recipe_dirs[@]}"; do
     # the build script; we don't care if the build itself fails —
     # we only need the post-sed source state, which the sed
     # commands apply before the actual build step).
-    ./target/release/repo cook "$name" >>"$log_file" 2>&1 || true
+    #
+    # A 600-second timeout is applied because some upstream
+    # recipes (e.g. kf6-kauth, kf6-kconfig, kf6-kwidgetsaddons)
+    # use autotools and their `autoreconf` step can take 5+
+    # minutes on a clean cook. The sed chain we care about
+    # is applied by the recipe's [build].script BEFORE the
+    # configure step, so a 10-minute window is plenty for the
+    # sed to apply (and the snapshot was already taken at
+    # Step 2, so even if the cook is killed by the timeout,
+    # the post-cook source state is still useful for the diff).
+    timeout 600 ./target/release/repo cook "$name" >>"$log_file" 2>&1 || true
 
     # Step 4: diff pristine vs post-cook.
     diff_out=$(diff -ruN "$pristine_dir" "$recipe_dir/source" \

local/scripts/tests/test_migrate_kf6_seds.py

@@ -206,6 +206,19 @@ class TestScriptStructure(unittest.TestCase):
         self.assertGreater(fetch_pos, 0, "fetch not found")
         self.assertLess(unfetch_pos, fetch_pos, "unfetch must come before fetch")
 
+    def test_cook_has_timeout(self):
+        # Some upstream KF6 recipes (kf6-kauth, kf6-kconfig,
+        # kf6-kwidgetsaddons) use autotools and the autoreconf
+        # step can take 5+ minutes. Without a timeout, a hung
+        # cook would block the migration script indefinitely.
+        # The script must apply a per-recipe timeout.
+        text = SCRIPT.read_text()
+        self.assertRegex(
+            text,
+            r'timeout\s+\d+\s+./target/release/repo\s+cook',
+            "cook call must be wrapped in `timeout N`",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()