[howdeploy]

Integrates the accepted platform contributions while retaining the original contributor commits.

Changes

• Extend @bbutterm's Windows desktop-window SDK from feat: add permissioned Windows desktop embedding for plugins #182 with the accepted Linux X11/XWayland implementation. The Windows native helper, service, IPC and reference plugin remain unchanged.
• Reuse browser viewport normalization and clipping; parent Linux windows to CanvasTTY and respect canvas visibility, HUD occlusions, layer order and native click focus.
• Include Linux permissions, packaging and the Linux Desktop reference plugin, with owner-bound single-use selections and restoration on detach and orderly shutdown.
• Include the four remaining commits from @teo-nex's fix(macOS): preserve PTYs, finish shutdown and fit usage reports #171: packaged usage checks, resilient macOS shutdown, compressed large usage-history snapshots with a downgrade exporter, and usage-report layout fixes.
• Include @bbutterm's fix: preserve Windows Codex screenshot paste with Ctrl+V #183: Windows Codex screenshot paste with Ctrl+V and configured paste shortcuts, preserving text and stale-session guards.
• Update the three existing browser/plugin fixtures for the shared visibility gate, separate desktop IPC registrars and renderer platform API. Keep all existing assertions.

Attribution and merge method

Merge with a merge commit, not squash or rebase. Original heads from #171 (038d73cb), #182 (7c9e6bca) and #183 (a10e6ee3) are ancestors of this branch; their authors and licenses remain in history. #172 was already included in main through 817ca7c5; its original PR has now been merged into its original beta2 target to record its accepted status.

Validation

• The repository owner manually accepted the Linux/XWayland attachment, movement and HUD layering behavior in DEV.
• Focused local browser/plugin/desktop, macOS history/shutdown, browser persistence and terminal shortcut checks pass.
• Local full root suite on Node 22: 2,646 tests, 2,636 passed, 10 skipped, zero failures. TypeScript checks, production build, benchmark contract checks and Even G2 companion tests pass.
• Automatic GitHub CI passes on this combined head: Linux verification and installers, Windows tests/typecheck/packaging, macOS tests/packaging/smokes, both mascot jobs, native macOS PTY resources and CanvasLink Android. See CI run 41251942369.
• The initial local sandbox run could not open test sockets; the successful full run used the normal host permissions.
• Settings-search styling is saved separately and is outside this PR.

Known limits

Linux requires X11/XWayland and XFixes 2; native Wayland surfaces and macOS desktop embedding are unsupported. Abrupt destruction of Electron can destroy foreign child windows and lose unsaved application data. Foreign GPU surfaces/dialogs and mixed DPI remain compatibility limits; Chromium-only captures may omit foreign pixels, and sampled native click focus can miss exceptionally short clicks. Windows native embedding and real Codex screenshot attachment were not manually retested here.