[wieslawsoltes]

Problem

Browser-workbench Code OSS does not load Electron's Linux selection-clipboard contribution, so its focused text selection never updates X11 PRIMARY.

Result

• Emits the exact one-way zero-ID CLIPBOARD_WRITE + REPLACE|PRIMARY + text/plain host request.
• Sources only settled, focused, connected, writable, non-password input/textarea selections.
• Caps publication at 64 KiB, rejects invalid UTF-8 and oversize values without truncation, and keeps the previous PRIMARY state on collapse or ineligible selection.
• Coalesces rapid changes by replacing at most one queued publication while preserving completion-bearing host requests and the aggregate queue cap.
• Suppresses input-intermediate checkpoints and flushes after settled task/microtask boundaries.
• Retires queued top-level and nested-frame stale publications during navigation/teardown.
• Exposes no JavaScript API or promise and logs no selected text.
• Adds focused contracts, including 10,000 same-task updates coalescing to one publication, and updates the Code OSS API ledger.

Readonly, contenteditable, general DOM Selection, and large/multicursor editor-model selection remain separate follow-up scope.

Closes #657.

Validation

git diff --check passed. Under the agreed fast merge policy, no local builds or runtime tests were run.