feat(i18n): add Phase 3 observability translations (EN + PL)

Added translations for all observability components:
- Validation warnings panel
- Auto-fixes badge
- AI reasoning process viewer
- Debug information panel
- Structured error display

English translations (en.json):
- observability_validationWarnings: "Validation Warnings"
- observability_autoFixesApplied: "Automatically adjusted"
- observability_aiReasoningProcess: "AI Reasoning Process"
- observability_debugInfo: "Debug Information"
- observability_model/duration/tokenUsage: Debug panel labels
- observability_validationFailed: "Safety validation failed"

Polish translations (pl.json):
- observability_validationWarnings: "Ostrzeżenia walidacji"
- observability_autoFixesApplied: "Automatycznie dostosowano"
- observability_aiReasoningProcess: "Proces rozumowania AI"
- observability_debugInfo: "Informacje debugowania"
- All debug panel labels translated
- observability_validationFailed: "Walidacja bezpieczeństwa nie powiodła się"

Updated components:
- ValidationWarningsAlert: Uses m.observability_validationWarnings()
- AutoFixBadge: Uses m.observability_autoFixesApplied()
- ReasoningChainViewer: Uses m.observability_aiReasoningProcess()
- MetadataDebugPanel: All labels now use i18n
- StructuredErrorDisplay: Translates error prefixes

All components now fully support English and Polish locales.

frontend/messages/en.json

@@ -216,6 +216,21 @@
   "suggest_summaryConstraints": "Constraints",
   "suggest_stepOptionalBadge": "optional",
 
+  "observability_validationWarnings": "Validation Warnings",
+  "observability_showMore": "Show {count} more",
+  "observability_showLess": "Show less",
+  "observability_autoFixesApplied": "Automatically adjusted",
+  "observability_aiReasoningProcess": "AI Reasoning Process",
+  "observability_debugInfo": "Debug Information",
+  "observability_model": "Model",
+  "observability_duration": "Duration",
+  "observability_tokenUsage": "Token Usage",
+  "observability_tokenPrompt": "Prompt",
+  "observability_tokenCompletion": "Completion",
+  "observability_tokenThinking": "Thinking",
+  "observability_tokenTotal": "Total",
+  "observability_validationFailed": "Safety validation failed",
+
   "medications_title": "Medications",
   "medications_count": [
     {

frontend/messages/pl.json

@@ -222,6 +222,21 @@
   "suggest_summaryConstraints": "Ograniczenia",
   "suggest_stepOptionalBadge": "opcjonalny",
 
+  "observability_validationWarnings": "Ostrzeżenia walidacji",
+  "observability_showMore": "Pokaż {count} więcej",
+  "observability_showLess": "Pokaż mniej",
+  "observability_autoFixesApplied": "Automatycznie dostosowano",
+  "observability_aiReasoningProcess": "Proces rozumowania AI",
+  "observability_debugInfo": "Informacje debugowania",
+  "observability_model": "Model",
+  "observability_duration": "Czas trwania",
+  "observability_tokenUsage": "Użycie tokenów",
+  "observability_tokenPrompt": "Prompt",
+  "observability_tokenCompletion": "Odpowiedź",
+  "observability_tokenThinking": "Myślenie",
+  "observability_tokenTotal": "Razem",
+  "observability_validationFailed": "Walidacja bezpieczeństwa nie powiodła się",
+
   "medications_title": "Leki",
   "medications_count": [
     {