Replace text aligner with jsdiff - #533

…ule (#543)

`scripts/CLAUDE.md` tells a session that a clean `git status` after
`scripts/vendor.py <bundle>` is the check that a bundle still matches
the script, and that the check holds only where every fetched input is
pinned. It then sorts the bundles into those two classes — and two of
the seven are in neither, so a session rebuilding `floating-ui` or
`mcp-app` has no answer for whether a diff it sees is drift to fix or an
upstream patch to take.

Each belongs in a class the paragraph already describes:

- `floating-ui` reproduces. `@floating-ui/dom`, `@floating-ui/core`, and
`@floating-ui/utils` are all in `PINS`, and that closure is complete:
`dom` depends on `core` and `utils`, `core` on `utils`, `utils` on
nothing. Rebuilding it left `git status` clean.
- `mcp-app` fetches an input `PINS` does not name.
`@modelcontextprotocol/ext-apps@1.7.5` declares `@standard-schema/spec
^1.1.0`, which npm's resolver picks, so the bundle sits with `plot` and
`pierre`. It reproduced when I rebuilt it today — which is exactly the
reading the paragraph exists to keep a session from relying on.

This is drift rather than a deliberate omission. The paragraph dates
from `c7b37062` (2026-08-30); `mcp-app` landed in #188 on 2026-09-01 and
`floating-ui` in #537 last night, and #533 — the most recent commit to
touch the paragraph — added `jsdiff` to it, so it is meant to be kept
current.

The test follows the shape this repo already uses for instruction lists
(#93, #105, #331, #496): it reads the bundle names out of `vendor.py`'s
`BUILDS` and `COPIES` rather than restating them, and asserts each is
named in that one paragraph. On `main` it fails with `unplaced in
scripts/CLAUDE.md: ['floating-ui', 'mcp-app']`.

What it deliberately does not check is *which* class a bundle is placed
in — deciding that means resolving each package's dependency graph,
which is a network call this suite should not make. A name in the wrong
class still needs a reader to catch; a name that is absent no longer
does.

<details><summary>Verification</summary>

- `uv run pytest tests/test_interact_layer.py` — 167 passed, 6 skipped.
- The new case alone, with `scripts/CLAUDE.md` reverted to `main`'s
text: `AssertionError: unplaced in scripts/CLAUDE.md: ['floating-ui',
'mcp-app']`.
- `scripts/vendor.py floating-ui` and `scripts/vendor.py mcp-app` each
left `git status` clean.
- `npm view @floating-ui/dom@1.8.0 dependencies` → `{
'@floating-ui/core': '^1.8.0', '@floating-ui/utils': '^0.2.12' }`;
`@floating-ui/core@1.8.0` → `{ '@floating-ui/utils': '^0.2.12' }`;
`@floating-ui/utils@0.2.12` → none;
`@modelcontextprotocol/ext-apps@1.7.5` → `{ '@standard-schema/spec':
'^1.1.0' }`.

</details>

Co-authored-by: leaf-agent <318509791+leaf-agent@users.noreply.github.com>