docs(#2775): align package-legitimacy docs to the ADR-0656 registry-API gate (#3010)

* docs(#2775): align package-legitimacy docs to the ADR-0656 registry-API gate

security-model.md, USER-GUIDE.md, ARCHITECTURE.md, COMMANDS.md,
FEATURES.md, and gsd-planner.md's STRIDE template (+ ja-JP mirrors)
described the pre-ADR-0656 design: slopcheck as the install-or-degrade
gate, with unavailability degrading every package to [ASSUMED].
ADR-0656 inverted this months ago — registry-API verdicts (npm/PyPI/
crates.io) are the gate; slopcheck is an optional escalate-only adapter
that no shipped configuration wires. Verified every replacement claim
against src/package-legitimacy.cts (checkPackages, classifyPackage,
lookupNpm/lookupPypi/lookupCrates) via Memtrace before writing it, so
the corrected prose matches the live implementation rather than
restating the ADR from memory.

Restored docs/explanation/security-model.md:79-84 (and its ja-JP
mirror) to original wording after an orthogonal spec review caught
that an earlier draft had edited the "Why WebSearch packages are
always [ASSUMED]" paragraph — inside the range issue #2775 explicitly
named as correct and to leave alone.

The ja-JP mirror was missing the closing clause present in the
corrected English original ("its absence leaves registry-API verdicts
intact rather than downgrading everything to [ASSUMED]") — added for
parity. This completes the ja-JP mirror the issue's acceptance
criteria named explicitly.

zh-CN/ko-KR/pt-BR (not named by #2775, but carrying the same stale
design) get the mechanical portion of the same fix: command-string
swaps, table headers, ARCHITECTURE.md diagram labels, and technical-
term swaps that reuse a word already attested elsewhere in the same
file (合法性/적법성/legitimidade for "legitimacy") — surrounding prose
untouched. The remainder in those three locales — full-paragraph
rewrites of the corrected degrade-path mechanism, deleted "External
dependency" bullets, and "manually install slopcheck" code blocks —
needs prose composed by a fluent speaker of each language and is filed
as open-gsd/gsd-core#3002 with an exact file:line inventory.

* test(#2775): acknowledge gsd-planner.md byte growth from the STRIDE-row fix

agents/gsd-planner.md grew 14 bytes (49309 -> 49323) from the STRIDE
supply-chain row correction (slopcheck -> package-legitimacy gate).
Emitted agent/workflow files are byte-tracked; this fragment
acknowledges the growth per tests/emitted-attribution.test.cjs's
"differential attribution over the real tree" check.

* docs(#2775): close ja-JP FEATURES.md gap; fix a ko-KR transliterated heading

docs/ja-JP/FEATURES.md:2808 still read the katakana transliteration
"スロップチェック verdict" in REQ-PKG-GATE-01 — invisible to a literal
"slopcheck" grep, so it was missed when ja-JP parity was checked and
declared complete. Corrected to "正当性判定" (legitimacy verdict),
matching the term already established in ja-JP/explanation/
security-model.md and ja-JP/USER-GUIDE.md. This was the only
remaining ja-JP gap; a full sweep for the transliterated form across
docs/ja-JP/ now returns zero hits, and the ja-JP mirror is genuinely
at parity.

docs/ko-KR/USER-GUIDE.md:398's heading "슬롭체크 판정:" had the same
transliteration problem. Fixed inline to "적법성 판정:", reusing the
적법성/legitimacy word already attested two lines below in the same
table. A parallel sweep of zh-CN and pt-BR found no transliterated
forms of "slopcheck" in either locale. The remaining transliterated
occurrence in ko-KR (USER-GUIDE.md:406, the lead-in to the
pip-install code block) needs prose composition like the rest of that
block and is added to open-gsd/gsd-core#3002's inventory.

* chore(#2775): backfill changeset PR number to 3010

---------

Co-authored-by: sim <sim@local>

docs/COMMANDS.md

@@ -227,13 +227,13 @@ Research, plan, and verify a phase.
 - With `--view`: print existing RESEARCH.md to stdout, no spawn. Errors if RESEARCH.md missing.
 
 **Package Legitimacy Gate (v1.42.1):**
-When the researcher recommends external packages, it runs `slopcheck install <pkg> --json` on each one and writes a `## Package Legitimacy Audit` table to RESEARCH.md recording Registry, Age, Downloads, Source Repo, and slopcheck verdict. Verdicts:
+When the researcher recommends external packages, it runs `gsd-tools query package-legitimacy check --ecosystem <npm|pypi|crates> <pkg>` on each one and writes a `## Package Legitimacy Audit` table to RESEARCH.md recording Registry, Age, Downloads, Source Repo, and legitimacy verdict. Verdicts are computed from live registry APIs (npm, PyPI, crates.io):
 
 - `[SLOP]` — package removed from RESEARCH.md entirely; never reaches the planner
 - `[SUS]` — package flagged; planner inserts `checkpoint:human-verify` before the install task
 - `[OK]` — package approved; no checkpoint added
 
-Packages sourced from WebSearch are tagged `[ASSUMED]` (not `[VERIFIED]`) and treated the same as `[SUS]` — they get a human checkpoint before install. If `slopcheck` cannot be installed, every recommended package is tagged `[ASSUMED]` and gated.
+Packages sourced from WebSearch are tagged `[ASSUMED]` (not `[VERIFIED]`) and treated the same as `[SUS]` — they get a human checkpoint before install. A failed registry lookup degrades to `[SUS]` rather than throwing, so it is gated, not silently accepted. `slopcheck` is an optional escalate-only adapter that no shipped configuration wires; it is not required for the gate to function.
 
 See [Package Legitimacy Gate in the User Guide](USER-GUIDE.md#package-legitimacy-gate-v1421) for the full checkpoint format, verdict table, and troubleshooting.