scaffold-project.py and adopt-project.py: the two tools spell a neutral_product_pins: entry differently, so 0x1F, 1_000, 1e3, 3dGlass and -x are bare from the scaffold and double-quoted from adopt #924

Goal: one spelling for a neutral_product_pins: entry, made by one function in scripts/shape_materialize.py that both tools call, so the same --pin writes the same line whichever tool made the root.

Filed by lane openRepoShape-3, from its triage of #459 at the v1.1.1 release commit 5017830. It is #459's line U034 (L2-15, which pairs with L2-14 on #457), one pull request's worth.

Two spellings of one entry (U034)

State. scaffold-project.py:1806-1826 (_neutral_pin_entry) writes the product bare wherever the project's own reader reads that line back as the product, and double-quotes it otherwise. adopt-project.py:13393-13405 (_neutral_pin_entry) writes y's plain-scalar spelling, and double-quotes where the reader does not read that back. PR #570 (#540) left this out: "Not covered here: L2-15 ... stays on #459".

What happens. A project that pins a product whose name begins with a digit or - gets a bare entry from the scaffold and a quoted one from adopt. Measured at 5017830 by loading both functions:

product   scaffold   adopt
0x1F      0x1F       "0x1F"
1_000     1_000      "1_000"
1e3       1e3        "1e3"
3dGlass   3dGlass    "3dGlass"
-x        -x         "-x"

openGlass, 007 and yes come out the same from both. The project's own reader reads every one back, and no gate fails. A standard YAML reader (PyYAML safe_load) misreads the scaffold's 0x1F as 31 and 1_000 as 1000; lane 2 counted 7,381 of the scaffold's spellings misread that way against 967 of adopt's, out of 377,891 admitted names.

Evidence. The lines and the probe above; #459's L2-15; PR #570's body.

Direction. Move adopt's rule (y's spelling, kept only where the reader reads it back) into scripts/shape_materialize.py, and call it from both tools. shape_materialize.py is not a pinned copy, so no project re-pins. Add a test that renders one list through both tools and compares the lines. This would also close L2-14 on #457.

Size: M.

Lane: openreposhape-3 (openRepoShape-3)