Suggest mode 5/7: inline suggestion operations

[adamsilverstein]

Part of #73411

What's in this PR

Adds the suggestion-specific layer on top of the marker primitive: create,
accept, and reject inline text (add/del) and formatting suggestions
(operations.js); the pure reconcilers that turn a text edit or a format
toggle into marker actions (reconcile-edit.js, reconcile-format.js); word/
line delete-range resolution; strip-markers for clean attribute snapshots;
findSuggestionText/findMarkerText helpers; and the annotate-suggestions hook.
Still pure modules - the keyboards and reconcilers that call them into the
live editor land in the final step.

Diagram

Pure transforms over a rich-text value: write a marker, resolve it on accept or reject, strip it for output.

Testing

This is one layer of the stack. To exercise the whole feature, #78994 bundles all seven layers into one branch and builds it in Playground:

👉 https://playground.wordpress.net/gutenberg.html?pr=78994

Enable Gutenberg > Experiments > Collaboration > Suggestion Mode, then follow the walkthrough in #73411, which also explains how to review the stack layer by layer.

---

Suggest mode stack

This rebuilds the manually-stacked Suggest mode work (#73411) as a GitHub Stack of 7 small, independently reviewable PRs, each building on the one below it:

1. #80427 - editor intent (edit/suggest/view) + experiment gate
2. #80428 - suggestion storage, REST controller, provider
3. #80429 - block-level capture (attribute + structural)
4. #80430 - inline marker primitive
5. #80431 - inline suggestion operations
6. #80432 - review UI (Apply/Reject sidebar + summary)
7. #80433 - inline live wiring, docs, e2e

The whole feature can be exercised end-to-end via the combined testing branch #78994 (Playground). Behind the "Suggestion Mode" experiment (Gutenberg > Experiments).

[github-actions]

Size Change: 0 B

Total Size: 7.83 MB

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[github-actions]

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[github-actions]

Flaky tests detected in 56c4083.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/31052261814
📝 Reported issues:

• [Flaky Test] can update custom URL link to a new custom URL link #80798 in /test/e2e/specs/editor/blocks/navigation.spec.js