fix: Defer textdomain loading to init action for WordPress 6.7+ compatibility (v0.4.8)

Fixes _load_textdomain_just_in_time notice and headers already sent warnings
on admin pages by deferring load_plugin_textdomain() and Settings tab label
initialization to the init action instead of plugins_loaded.

Co-Authored-By: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -34,7 +34,9 @@ This project is proudly **"vibe-coded"** using Claude.AI - the entire codebase w
 
 **Note for AI Assistants:** Clean this section after the specific features are done or new releases are made. Effective changes are tracked in `CHANGELOG.md`. Do not add completed versions here - document them in the Session History section at the end of this file.
 
-*No pending roadmap items.*
+### Known Bugs
+
+*No known bugs at this time.*
 
 ## Technical Stack
 
@@ -288,6 +290,22 @@ add_action( 'wp_prometheus_collect_metrics', function( $collector ) {
 
 ## Session History
 
+### 2026-02-07 - Fix Early Textdomain Loading (v0.4.8)
+
+- Fixed `_load_textdomain_just_in_time` warning on admin pages (WordPress 6.7+ compatibility)
+- Root cause: `load_plugin_textdomain()` was called during `plugins_loaded` in `Plugin::__construct()`
+- WordPress 6.7+ requires textdomain loading at the `init` action or later
+- Two changes made:
+  - `Plugin.php`: Deferred `load_textdomain()` to `init` action hook, changed method visibility to public
+  - `Settings.php`: Deferred tab label initialization (which uses `__()`) to a lazy `get_tabs()` method
+- Cleared Known Bugs section — no remaining known issues
+- **Key Learning**: WordPress 6.7 textdomain loading requirements
+  - `load_plugin_textdomain()` must be called at `init` or later
+  - WordPress's JIT textdomain loader (`_load_textdomain_just_in_time`) also triggers too-early warnings
+  - Any `__()` / `_e()` calls before `init` for a plugin textdomain will trigger the notice
+  - The warning causes "headers already sent" errors because the notice output breaks header modifications
+  - Solution: Defer both explicit `load_plugin_textdomain()` and any `__()` calls to `init` or later hooks
+
 ### 2026-02-03 - Database Query Timing Documentation (v0.4.7)
 
 - Added database query duration distribution panel to Grafana Runtime dashboard