feat: vendor hardened Unity-Unterm

[dudetru25]

Summary

• Vendors the audited rankupgames/Unity-Unterm fork at commit b056990babba629c8505a345ddc5a7a2d845ad6d into the canonical toolkit package and its internal smoke-project mirror.
• Incorporates upstream tnayuki/Unity-Unterm through ead1391bd38532eebfb9f13f10064eddc372b769 without dropping fork hardening.
• Adds terminal, Claude Code, code editor, debugger, and settings aliases under Tools > Unity Cursor Toolkit > Unterm.
• Restores the terminal tab icon across reloads/title changes and reduces idle repaint, texture, native resize, file, and diff work.
• Removes the Claude Code downloader; the optional panel only discovers an existing user-managed executable.
• Adds the attested macOS/Windows debugger binaries and preserves an audited target-scoped Linux/X11 dependency path for future Linux debugging.

MCP safety

• Unity-Unterm MCP remains disabled and dormant by default.
• Each project can select Prompt, Allow Mutating, or Allow Dangerous without committing machine-specific approval state.
• Arbitrary C# requires a separate explicit full-machine-access opt-in.
• Unknown or newly added tools remain fail-closed and cannot inherit automatic dangerous-action approval.
• Disabling MCP drains pending work and clears managed state.

Platform and dependency scope

• The current embedded source-pane renderer and shipped native debugger binaries remain macOS/Windows only.
• CI verifies the future Linux/X11 feature graph and rejects accidental Wayland activation.
• Wayland is intentionally deferred because its current transitive quick-xml graph is covered by active RustSec advisories.

Security and supply chain

• Unity-Unterm and the fork modifications remain covered by the upstream MIT license.
• Native artifacts were built on GitHub-hosted runners and bound to the reviewed workflow, source branch, and exact commit.
• All 80 vendored files, legal notices, native libraries, and debugger executables are SHA-256 pinned in both mirrors.
• Fork build: https://github.com/rankupgames/Unity-Unterm/actions/runs/29296790454
• Attestation: https://github.com/rankupgames/Unity-Unterm/attestations/35175215

Validation

• npm run validate passed TypeScript compilation, unused-code checks, 205 tests, vendor verification, and both npm audits.
• Local installed vsce package --no-dependencies packaging smoke passed without installing or updating dependencies.
• Vendor validator confirmed both 80-file mirrors at the pinned fork commit.
• Exact gh attestation verify policy passed for four native artifacts, third-party notices, SBOM, and source manifest.
• Fork CI passed supply-chain, macOS, Windows, Linux/X11 dependency-intent, audit, deny, and provenance checks.
• The existing WIA Unity 6000.3.9f1 editor resolved toolkit commit 0cb003d59936eae91618409179bd6cbf438ee04c, loaded the attested native hashes, showed zero Console errors, exposed all five toolkit menu entries, kept the terminal icon through an OSC title change, and displayed no Claude downloader in Preferences. Unity 6000.3.19 also compiled the vendored production and test assemblies in the disposable smoke project.

Related work

• Initial hardened fork: Harden Unterm for Unity Cursor Toolkit vendoring Unity-Unterm#1
• Upstream-preserving fork sync: Merge latest upstream and preserve fork hardening Unity-Unterm#2
• Icon, performance, Claude discovery, Linux intent, and MCP policy follow-up: Improve editor performance and MCP controls Unity-Unterm#3
• Isolated DEV-2/WispKey worker preparation: Add isolated Firecracker build worker profile boring-computers#1