release: prepare v0.4.1 with macOS desktop and runtime fixes

[jiayuqi7813]

This sync prepares Muteki 0.4.1 with the current Web, Agent runtime, penetration-testing workbench, and macOS desktop client.

Credential deletion and reference cleanup now run outside the Web event loop. Removing a credential used by completed conversations no longer blocks unrelated requests. The isolated regression exercised reference cleanup and filesystem deletion; with a 350 ms simulated detach, the health request improved from about 359 ms under the previous route shape to about 1.2 ms.

Closes #199.

Release changes

• Update package versions, release metadata, Compose images, Worker build defaults, and English/Chinese release documentation to 0.4.1.
• Include unified Web/desktop settings, Agent compatibility and recovery fixes, usage/notification views, and the bundled local desktop runtime.
• Build macOS Apple-silicon and Intel DMG/ZIP assets with distinct architecture names. Verify signatures, bundled runtime architecture, authenticated backend startup, and rendered chat before publishing.
• Keep Linux amd64/arm64 containers for Web, UI, full Worker, and slim Worker. Do not build Windows or Linux desktop packages.
• Document that this release's macOS packages are ad-hoc signed, not notarized, and require manual desktop updates.
• Refresh generated OpenAPI contracts and exclude internal development metadata from the public snapshot.

Validation

• Public snapshot scan, locked Python dependency sync, Go build, Web TypeScript check, and production Web build.
• Generated schema and OpenAPI consistency checks; product entry-point imports.
• Desktop unit tests (16 passed), desktop TypeScript check, and conversation selection/preferences regressions.
• Local macOS arm64 DMG/ZIP packaging, deep signature verification, and isolated packaged-app acceptance check passed.
• Focused 对话无法删除，导致Agent凭借无法删除 #199 regression with temporary credentials and mocked references; no live user data was modified.
• macOS Intel packaging and both-architecture container publication are gated by the release workflow.