docs(changelog): stub-bun wording matches what the fixtures check (GSTA-97)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -15,7 +15,7 @@
 ### Tests
 - `test/setup-production-deps.test.ts`: `install_runtime_deps`, sliced out of `setup` and run against a recording `bun` that models Bun's frozen `--production`, passes `--production` on the frozen-lockfile call, refreshes a stale lockfile before retrying, and stops setup when the refresh fails. A checkout with the dev toolchain gets the full frozen install, and a failed full install stops setup too. A walk of `bun.lock`'s production closure (with required-peer and optional-peer controls) proves no production dependency brings in `typescript`, the marker setup checks. The real-Bun rows run with `HOME`, `XDG_CONFIG_HOME` and `BUN_CONFIG_*` isolated, so a developer's global `.bunfig.toml` cannot change them. Run with the real Bun on local `file:` packages: a fresh install leaves out devDependencies, a later production install keeps the ones a full install added, and a stale lockfile is refreshed while the install stays production-only. No other line in `setup` calls `bun install` (the pre-change line is the negative control). `bin/dev-setup`'s install block, run over an existing `node_modules`, still calls plain `bun install`. A scan of every shipped file (`bin`, `lib`, `browse/src`, `design/src`, `make-pdf/src`, `hosts`, `extension`, the resolvers, and the scripts `setup` and the build call by path) finds no import or `require` of a package outside `dependencies`. Modules the shipped code reaches by relative import (gen-skill-docs' `scripts/` helpers, and the `test/helpers/providers` modules `gstack-model-benchmark` loads) are scanned too. Negative controls: a planted Agent SDK import is caught, including one split over several lines and a re-export; a type-only import is not; and moving `@anthropic-ai/sdk` back to dev flags `gstack-distill-free-text`. The packages `bun run build` copies out of `node_modules` are production dependencies.
 - `test/gstack-browser-ensure.test.ts`: with `node_modules` missing, the preflight runs the frozen production install, refreshes a stale lockfile before retrying, and ends a failed install in `BROWSER_UNAVAILABLE` with a production-install fix line.
-- The install fixtures' stub `bun` (`test/helpers/install-fixture.ts`, `test/helpers/claude-overlay-fixture.ts`, `test/team-mode.test.ts`) now matches `install --production --frozen-lockfile`, so a setup that dropped the flag would reach the real `bun` instead of the stub.
+- The install fixtures' stub `bun` (`test/helpers/install-fixture.ts`, `test/helpers/claude-overlay-fixture.ts`, `test/team-mode.test.ts`) now matches `install --production --frozen-lockfile`. The team-mode stub fails on any other argv; the two helper stubs hand other commands to the real `bun`, so for them the new argv is a match, not a regression check.
 
 ### Gate integrity
 - No threshold, budget, timeout, trial count, case kind or assertion was weakened. The four stub patterns (in three files) changed to the new argv only.