Vision 2: anchored continuation of curated flow (v1.3.0)

[seangoogoo]

Summary

• Refactors the block to honor all native core/query filters (taxonomy, author, keyword, sticky modes) while preserving the anchor+wrap semantic that is this plugin's sole value-add.
• Removes the custom excludeSticky toggle (the Drawbridge annotation that kicked off this refactor).
• Deletes inspector-controls.js; reduces lock-custom-query.js to only lock the Query Type toggle.
• REST middleware now sends a single JSON sequential_query_attrs param for editor-server parity on any filter combination.

Design doc

See docs/plans/2026-04-20-vision-2-curated-flow-design.md (local, not tracked).

Test plan

• Unit tests pass (`composer test:unit`) — 15 / 17
• Integration tests pass (`composer test:integration`) — 44 / 84
• Build clean (`npm run build`)
• Manual QA in wp-test via Chrome DevTools MCP: frontend renders match `SequentialResolver` expectations for each sticky mode; editor sidebar shows native Sticky / Ordering / Filters panels; Query Type toggle stays hidden; REST middleware sends `sequential_query_attrs` JSON on every attribute change; v1.2.2 sticky-neutralization regression still green.
• CI green on all 3 matrix jobs (this PR will trigger it)