docs: refresh README for v1.0.12 + WordPress.org launch

[odanree]

Summary

Brings the GitHub-facing README in sync with what actually shipped. The previous version was stuck at `Version: 1.0.3` and had missed nine releases of changes; with the WP.org listing now live, anyone landing on the repo for the first time should see an accurate picture.

What changed

Accuracy fixes

Where	Before	After
Top description + Performance Benchmarks + Performance Impact table	`1.8s LCP / 0.8s FCP`	`1.4s LCP / 1.0s FCP` — now matches `readme.txt` so the two docs no longer contradict each other
Configuration section	`Settings > Image Optimizer`	Top-level ODR Image Optimizer entry with a Settings submenu (matches `add_menu_page` in `class-core.php`; menu has been top-level since 1.0.4)
Configuration toggle	`Remove Bloat Scripts`	`Kill Bloat` — matches the toggle label users see and the `kill_bloat` setting key in `class-settings.php`
Footer	`Version: 1.0.3` + `Email: danhle@danhle.net`	`Version: 1.0.12` + email removed (same scraping concern that drove the removal from `readme.txt` in 1.0.10)

Stale 'in progress' notes cleaned

Both the LSP and DIP sections had `Status: ~95% Implemented` / `Status: ~85% Implemented, Improving` headers with `What's Being Improved` lists. The work in those lists landed releases ago. Both sections now read as `Fully Implemented` with the improvements folded into the prose.

New beats

• WordPress.org badge + callout at the top, linking to the live listing and forward-pointing to the new Release Flow section.
• Release Flow section documenting the GitHub → SVN auto-deploy:
  • The `v*` tag trigger
  • The 10up/action-wordpress-plugin-deploy hand-off
  • Required repo secrets (`WPORG_SVN_USERNAME`, `WPORG_SVN_PASSWORD`)
  • The one-line `git tag && git push` release ritual
• Security & Compliance gained two bullets: the backup-storage compliance rule (under `wp_upload_dir()`, never inside the plugin folder — the 1.0.8 fix) and the `uninstall.php` cleanup.
• CLAUDE.md added to the Architecture Documentation list so new contributors find the release checklist + compliance constraints in one click.

Also

• `.private/` added to `.gitignore` (a local-only directory holding drafts like the LinkedIn launch post we put together this evening; it should never be committed or shipped).

Test plan

• No code changes; doc-only PR. Quality checks will still run since they include markdown lint.
• All three places that quote LCP/FCP numbers now agree (top description, Performance Benchmarks list, Performance Impact table).
• Admin menu location matches what the code does (`add_menu_page` in `class-core.php:151`).
• Toggle name matches the UI (`Kill Bloat` in both the readme `FAQ` and the README `Configuration` section).
• Personal email no longer appears anywhere in the repo's user-facing docs.