revert: fix(surface) #3666 — CONTRIBUTING.md test-pattern violations (#3688)

Reverts c5657fcbfd (squash of PR #3666).

The production change was correct in intent. The new test file
tests/surface-state.test.cjs violates two CONTRIBUTING.md rules
that the project enforces specifically because they produce
passing-but-useless tests:

  1. ~15 try { ... } finally { cleanup(dir); } blocks in test bodies
     — CONTRIBUTING.md "Never use try/finally inside test bodies."
     Approved forms are beforeEach/afterEach hooks or t.after(...).

  2. 17 assert.match calls on rendered console.warn prose
     — CONTRIBUTING.md "Prohibited: Raw Text Matching on Test
     Outputs." Tests must assert on a typed structured surface
     (frozen reason enum) instead of the rendered prose, otherwise
     they pass-but-rot the moment a warning string is reworded.

The .changeset/witty-birds-gather.md fragment is also reverted so
the v1.43 changelog does not advertise a fix that is not on main.

A reworked PR addressing items 1-4 from the re-review (linked on
the closed PR thread) is welcome — the intent of the fix is right.

Refs #3666 #3662

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.changeset/witty-birds-gather.md

@@ -1,5 +0,0 @@
----
-type: Fixed
-pr: 3666
----
-**`readSurface()` no longer silently degrades partial `.gsd-surface.json` to the `full` profile** — missing optional array fields (`disabledClusters`, `explicitAdds`, `explicitRemoves`) now default to `[]` so a hand-edited surface state with only some fields keeps working. Hard validation failures (unreadable file like `EACCES`, malformed JSON, non-object root, missing/non-string/blank/comma-only `baseProfile`) still return `null` but now emit a `console.warn` diagnostic naming the file and reason instead of failing silently. Unknown profile names in `baseProfile` (e.g. a typo like `"standrad"`) warn — they were previously swallowed by `resolveProfile()`'s fallback-to-`full`. Optional array fields with the wrong type (e.g. `disabledClusters: "utility"`) also warn before being coerced to `[]`. `writeSurface()` normalizes its input symmetrically — partial inputs are completed before being written, blank/non-string/comma-only `baseProfile` throws `TypeError`, and unknown profile names plus wrong-typed optional fields warn — so the writer/reader asymmetry that produced the original bug cannot recur. (#3662)