Docs: fix fabricated security claims, phantom hooks, stale requirements

[vapvarun]

Documentation accuracy + coverage pass for v1.3.2. Every claim was verified against source with grep before editing. Doc files only - no code or dist/ changes.

P0 Accuracy - fabricated security removed

• Nonce claims removed (developer-guide.md + faq-guide.md): wp_verify_nonce, X-WP-Nonce header, ajax_nonce config field, and "nonce verification on all AJAX requests". Source has zero wp_verify_nonce/check_ajax_referer on the load-more path; the JS explicitly notes "No nonce here on purpose" (read-only cached GET). The per-visitor nonce was dropped in 1.3.0 for page-cache compatibility - docs now explain why instead of claiming verification.
• Rate limiting claim removed (faq-guide.md): check_rate_limit / infinite_loader_rate_limit were removed in 1.3.2; no remnants in source.

Phantom / mislabeled

• Removed phantom filters infinite_loader_loading_types and infinite_loader_load_more_button_html (do not exist).
• Relabeled the 5 "Frontend Actions" as jQuery $(document).trigger() events - the plugin fires no frontend do_action.
• Corrected the AJAX handler location: Infinite_Loader_For_Woocommerce_Admin::handle_infinite_loader_ajax on template_redirect (Admin class, not Public), renders products-only, no nonce.
• Fixed stale requirements to WP 6.5 / PHP 8.0 (user-guide.md + faq-guide.md).
• Fixed phantom version 1.2.4 references (changelog jumps 1.2.2 -> 1.3.0; those features shipped in 1.3.0).
• README.txt Tested up to: 7.0 -> 6.9 (WP 7.0 does not exist).

Coverage

• Documented 8 real but undocumented filters: should_load_assets, js_function, next_page_selector, prev_page_selector, previous_btn_hover_css, for_woocommerce_load_previous_button_style, wbcom_infinite_loader_image, settings_nav_groups.
• Added an EDD licensing/activation section (option keys, activate/deactivate, update flow).
• README.txt (the only doc shipped to customers - guides are .distignored): added a settings overview and a developer-hooks pointer.

Extra finding (also fixed in docs)

• CAPABILITIES.md corrected: real EDD license option keys (edd_wbcom_infinite_loader_license_key/_status), removed the stale rate-limit transient, version 1.3.1 -> 1.3.2.

Code bug found (NOT fixed here - out of doc scope)

uninstall.php deletes infinite_loader_license_key/_status and transient infinite_loader_license_data, but the license code actually writes edd_wbcom_infinite_loader_license_key/_status and transient edd_wbcom_infinite_loader_license_key_data. License options are never cleaned up on uninstall. Worth a follow-up fix.

Version was NOT bumped.