fix: disable img sizes=auto to mitigate Gutenberg bug (1.2.2)

[nickpagz]

Summary

Emergency mitigation. WordPress 6.7+ automatically adds a sizes="auto" attribute to lazy-loaded images via the wp_img_tag_add_auto_sizes filter. A Gutenberg bug in this behavior is affecting potentially hundreds of partner sites, and the upstream fix — WordPress/gutenberg#80386 — has no confirmed release date.

This PR disables the auto-sizes behavior fleet-wide so we don't have to wait on a Gutenberg release:

add_filter( 'wp_img_tag_add_auto_sizes', '__return_false' );

Where it lives / why

Registered in Plugin::initialize() (a new register_core_compat_filters() helper) rather than behind a module, so it runs on every active install regardless of module settings — enabling the fastest possible blanket rollout. The helper is clearly marked temporary and links the Gutenberg PR so it's easy to find and remove once the upstream fix ships.

Safety

• add_filter() + __return_false are both WordPress core — no version/dependency risk.
• The filter only fires during image-tag rendering; harmless where the attribute wasn't being added.
• No error/notice if the hook is absent — registration is inert until the filter runs.

Version

Patch bump 1.2.1 → 1.2.2 (a8csp-atlantis.php header + @version, package.json), per the release checklist in README.md.

Follow-up

Revert register_core_compat_filters() (or just the single line) once the Gutenberg fix is released and has propagated to sites.

🤖 Generated with Claude Code

[t51eng-poseidon]

🔱 Poseidon started reviewing this PR — central run.

[t51eng-poseidon]

🔱 Poseidon Review

Summary — Emergency fleet-wide mitigation that disables the WordPress 6.7+ sizes="auto" image attribute via a new register_core_compat_filters() helper; low risk, correct filter name, no issues found on this pass.

• 🐛 Fix — Registers add_filter( 'wp_img_tag_add_auto_sizes', '__return_false' ) in Plugin::initialize() to work around the upstream Gutenberg bug.
• 🔧 Chore — Patch version bump 1.2.1 → 1.2.2 across a8csp-atlantis.php and package.json.

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ℹ️ Review info

• Commit: 831cdb4
• Files reviewed: a8csp-atlantis.php, package.json, src/Plugin.php
• Files skipped: none
• Model: claude-opus-4-8