🔥 feat(rendering): Handle rendering concerns framework-agnostic, prove with Web components

[Charles Hudson (phobetron)]

Summary

This introduces a framework-agnostic presentation layer for optimized entry rendering and uses it from both the React Web SDK and the new Web Components surface.

Key changes:

• Add @contentful/optimization-web/presentation with shared optimized-entry snapshot logic, loading/fallback behavior, live-update locking, host tracking attributes, duplicate-baseline nesting state, and optimization root SDK binding helpers.
• Add @contentful/optimization-web/web-components with ctfl-optimization-root, ctfl-optimized-entry, and defineContentfulOptimizationElements.
• Refactor React OptimizedEntry to consume the shared presentation controller instead of duplicating presentation, loading, tracking-attribute, and live-update logic.
• Keep optimized entry hosts as display: contents wrappers, with tracking attributes applied to the host.
• Update the Web SDK dev harness and Vanilla reference implementation to use Web Components as the primary integration pattern.
• Expand Vanilla Web SDK E2E coverage for Web Components-based display, click, hover, view, consent, preview, live updates, offline recovery, and manual view tracking.
• Keep one lean manual-tracking example with coverage proving it does not double-track.
• Update bundle-size tooling so JavaScript entry budgets include reachable local split chunks, then adjust affected budgets accordingly.

Notes for reviewers

• Web Components intentionally do not fetch or render entry content. They bind SDK state, host tracking attributes, and lifecycle events; the consumer renders content in response to resolved entry data.
• data-ctfl-entry-id continues to represent the currently rendered entry, starting from baseline and updating to the variant after resolution.
• data-ctfl-baseline-id is preserved for optimization-backed entries.
• Loading/fallback states intentionally avoid tracking attributes until resolved, preserving React behavior.
• The Web Components bundle-size budget increase reflects the now-budgeted reachable runtime chunks, including the display-contents view-tracking support from main.

Validation

Passed:

• pnpm --filter @contentful/optimization-web typecheck
• pnpm --filter @contentful/optimization-web test:unit — 276 passed
• pnpm --filter @contentful/optimization-web build
• pnpm --filter @contentful/optimization-web size:check
• pnpm --filter @contentful/optimization-react-web typecheck
• pnpm --filter @contentful/optimization-react-web test:unit — 93 passed
• pnpm --filter @contentful/optimization-react-web build
• pnpm --filter @contentful/optimization-react-web size:check
• pnpm lint
• pnpm build:pkgs
• pnpm implementation:run -- web-sdk typecheck
• pnpm implementation:run -- web-sdk build
• pnpm implementation:run -- web-sdk implementation:test:e2e:run — 99 passed
• pnpm implementation:run -- react-web-sdk typecheck
• pnpm implementation:run -- react-web-sdk build
• pnpm implementation:run -- react-web-sdk implementation:test:e2e:run — 84 passed
• pnpm exec eslint implementations/web-sdk implementations/react-web-sdk
• pnpm size:check
• git diff --check

[NT-3484]