feat: support resource replacement in CodeMirror

[Maxxich]

Depends on PR: feat: support resource replacement in ProseMirror

Parse inserted Markdown fragments using shared editor dependencies and serialize
the current document when applying replacements. Guard local history while requests
are queued or pending, validate service dispatch, and release completed operations
with effect-only cleanup. Include Markdown, history, cleanup and standalone CM tests.

Summary by Sourcery

Support asynchronous resource replacement in CodeMirror while protecting local history and validating replacement lifecycle operations.

New Features:

• Add CodeMirror resource replacement support for pasted and dropped Markdown resources using the shared parser and serializer.
• Support asynchronous replacement application with validation, history isolation, and integration with the resource replacement controller.

Bug Fixes:

• Prevent local undo and redo from bypassing queued or pending resource replacement operations.
• Ensure completed, rejected, failed, or destroyed operations release their temporary state without affecting other operations.
• Reject replacement requests when the editor changes, dispatch is filtered or overridden, or the editor is no longer editable.

Enhancements:

• Expose CodeMirror history-lock state and make undo/redo commands and depth queries respect it.
• Add standalone Markdown resource collection and replacement utilities with support for configured resource types, URL validation, opaque identifiers, and precise text changes.

Tests:

• Add comprehensive CodeMirror regression, Markdown processing, history-lock, cleanup, dispatch-contract, and integration coverage.

[gravity-ui]

[gravity-ui]

[sourcery-ai]

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