feat(sandbox): add buffer to QuickJS module registry

[kwburns-kong]

Extends the existing ambient Buffer shim (sandbox-globals.ts) with slice/subarray/indexOf/lastIndexOf/includes/compare/equals/fill, verified against real Node's Buffer. Adds require('buffer') as a thin re-export — Buffer itself stays an ungated ambient global (as before), so the module grant adds no new restriction; documented explicitly in PERMISSIONS.md rather than implied. Also adds a narrow, documented allowlist entry to findLeakedGatedReferences for this intentional require('buffer').Buffer === globalThis.Buffer alias (matches real Node's own identity).

Part of the legacy-module porting plan (packages/insomnia/src/templating/sandbox/plans/). Milestone 4a; security review (4b) is a separate pass.

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Security review (4b): completed. Buffer's ambient/ungated status was confirmed to predate this PR (introduced in #10220's M2 pass, not widened here); slice()/subarray()'s shared-memory semantics, fill()'s throw-on-non-numeric behavior, and the findLeakedGatedReferences allowlist reasoning were all independently re-verified and hold. One correctness bug was found and fixed directly on this branch: indexOf()/includes() returned -1 instead of the real-Node-matching clamped this.length for an empty needle past the buffer's end; fixed with a new parity regression test. Full detail in packages/insomnia/src/templating/sandbox/SANDBOX-SECURITY-FINDINGS.md (local, uncommitted working doc — not part of this diff).

[github-actions]

✅ Circular References Report

Generated at: 2026-08-10T18:58:20.056Z
Status: ✅ NO CHANGE

Summary

Metric	Base (develop)	PR	Change
Total Circular References	9	9	0 (0.00%)

Click to view all circular references in PR (9)

insomnia-inso/src/db/models/types.ts -> insomnia-inso/src/db/types.ts
insomnia/src/main/prompt-bridge.ts -> insomnia/src/main/window-utils.ts -> insomnia/src/main/plugin-window.ts
insomnia/src/main/window-utils.ts -> insomnia/src/main/plugin-window.ts
insomnia/src/network/network.ts -> insomnia-scripting-environment/src/objects/index.ts -> insomnia-scripting-environment/src/objects/collection.ts -> insomnia-scripting-environment/src/objects/response.ts
insomnia/src/network/network.ts -> insomnia/src/common/render.ts
insomnia/src/ui/components/settings/import-export.tsx -> insomnia/src/ui/components/modals/export-requests-modal.tsx
insomnia/src/ui/components/tabs/tab-list.tsx -> insomnia/src/ui/components/tabs/tab.tsx
insomnia/src/ui/components/templating/tag-editor-arg-sub-form.tsx -> insomnia/src/ui/components/templating/external-vault/external-vault-form.tsx
insomnia/src/ui/components/viewers/response-viewer.tsx -> insomnia/src/ui/components/viewers/response-multipart-viewer.tsx

Click to view all circular references in base branch (9)

insomnia-inso/src/db/models/types.ts -> insomnia-inso/src/db/types.ts
insomnia/src/main/prompt-bridge.ts -> insomnia/src/main/window-utils.ts -> insomnia/src/main/plugin-window.ts
insomnia/src/main/window-utils.ts -> insomnia/src/main/plugin-window.ts
insomnia/src/network/network.ts -> insomnia-scripting-environment/src/objects/index.ts -> insomnia-scripting-environment/src/objects/collection.ts -> insomnia-scripting-environment/src/objects/response.ts
insomnia/src/network/network.ts -> insomnia/src/common/render.ts
insomnia/src/ui/components/settings/import-export.tsx -> insomnia/src/ui/components/modals/export-requests-modal.tsx
insomnia/src/ui/components/tabs/tab-list.tsx -> insomnia/src/ui/components/tabs/tab.tsx
insomnia/src/ui/components/templating/tag-editor-arg-sub-form.tsx -> insomnia/src/ui/components/templating/external-vault/external-vault-form.tsx
insomnia/src/ui/components/viewers/response-viewer.tsx -> insomnia/src/ui/components/viewers/response-multipart-viewer.tsx

Analysis

✅ No Change: This PR does not introduce or remove any circular references.

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This report was generated automatically by comparing against the develop branch.