diff_171.patch

diff --git a/.gitignore b/.gitignore
index 8cffc34..137cd8e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,6 @@ venv
 __pycache__
 *.ps1
 
-<<<<<<< HEAD
 # Environment / secrets (never commit real credentials)
 .env
 .streamlit/secrets.toml
@@ -10,9 +9,6 @@ __pycache__
 # Data directory (created at runtime)
 data/
 
-# OS artefacts
-.DS_Store
-Thumbs.db
 # IDE / editor
 .vscode/
 .idea/
diff --git a/config.py b/config.py
index 2b7a1ab..2e3548f 100644
--- a/config.py
+++ b/config.py
@@ -134,3 +134,7 @@ def get_optional(key: str, default: str | None = None) -> str | None:
 ANALYTICS_RETENTION_DAYS: int = int(os.getenv("SPAMLYSER_ANALYTICS_RETENTION", "90"))
 
 BATCH_RATE_LIMIT = 50
+
+# ΓöÇΓöÇ Error boundary / resilience ΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇ
+ERROR_BOUNDARY_ENABLED: bool = os.getenv("SPAMLYSER_ERROR_BOUNDARY", "true").lower() == "true"
+ERROR_BOUNDARY_SHOW_DETAIL: bool = os.getenv("SPAMLYSER_ERROR_DETAIL", "false").lower() == "true"
diff --git a/models/__init__.py b/models/__init__.py
index 66834c5..1d97d98 100644
--- a/models/__init__.py
+++ b/models/__init__.py
@@ -22,6 +22,15 @@
     save_custom_rules,
 )
 from .encrypted_report import ReportEncryptor
+from .error_boundary import (
+    ConfigurationError,
+    DataAccessError,
+    ModelLoadError,
+    PageError,
+    error_boundary,
+    render_error_panel,
+    safe_execute,
+)
 from .export_feature import export_results_button
 from .language_detector import detect_language, is_language_supported
 from .message_categorizer import MessageCategorizer
@@ -48,11 +57,16 @@
     "THREAT_CATEGORIES",
     "BatchProcessor",
     "ConfidenceCalibrator",
+    "ConfigurationError",
+    "DataAccessError",
     "MessageCategorizer",
+    "ModelLoadError",
+    "PageError",
     "ReportEncryptor",
     "SenderReputation",
     "SimpleExplainer",
     "StorageManager",
+    "ThemePreset",
     "WebhookNotifier",
     "WordAnalyzer",
     "agreement_score",
@@ -63,6 +77,7 @@
     "confidence_distribution",
     "default_json_validator",
     "detect_language",
+    "error_boundary",
     "evaluate_compound_rule",
     "evaluate_condition",
     "export_results_button",
diff --git a/models/error_boundary.py b/models/error_boundary.py
new file mode 100644
index 0000000..44c05be
--- /dev/null
+++ b/models/error_boundary.py
@@ -0,0 +1,103 @@
+"""Error boundary framework ΓÇö wraps page functions with graceful error handling."""
+
+import functools
+import logging
+import traceback
+from typing import Any, Callable, TypeVar
+
+import streamlit as st
+
+logger = logging.getLogger(__name__)
+
+F = TypeVar("F", bound=Callable[..., Any])
+
+
+class PageError(Exception):
+    """Base exception for Spamlyser page-level errors."""
+
+    def __init__(self, message: str, page: str = "", recoverable: bool = True):
+        super().__init__(message)
+        self.page = page
+        self.recoverable = recoverable
+
+
+class ModelLoadError(PageError):
+    """Raised when a model fails to initialise."""
+
+
+class DataAccessError(PageError):
+    """Raised when storage reads/writes fail."""
+
+
+class ConfigurationError(PageError):
+    """Raised when the app config is invalid."""
+
+
+def error_boundary(page_func: F, fallback_message: str | None = None) -> F:
+    """Decorator that wraps a Streamlit page function in a try/except block.
+
+    On failure it logs the traceback and renders a user-friendly error panel
+    instead of crashing the whole app.
+    """
+    @functools.wraps(page_func)
+    def wrapper(*args, **kwargs):
+        try:
+            return page_func(*args, **kwargs)
+        except PageError as exc:
+            logger.error(
+                "PageError in %s (recoverable=%s): %s",
+                exc.page or page_func.__name__,
+                exc.recoverable,
+                exc,
+            )
+            render_error_panel(
+                title=f"⚠️ {exc.page or page_func.__name__} Error",
+                message=str(exc),
+                detail=traceback.format_exc() if exc.recoverable else None,
+                recoverable=exc.recoverable,
+            )
+        except Exception as exc:
+            logger.error("Unhandled error in %s: %s", page_func.__name__, exc, exc_info=True)
+            render_error_panel(
+                title="⚠️ Unexpected Error",
+                message=fallback_message or "Something went wrong. Please try again.",
+                detail=traceback.format_exc(),
+                recoverable=True,
+            )
+    return wrapper  # type: ignore[return-value]
+
+
+def render_error_panel(
+    title: str = "⚠️ Error",
+    message: str = "An error occurred.",
+    detail: str | None = None,
+    recoverable: bool = True,
+) -> None:
+    """Display a styled error panel in the Streamlit UI."""
+    st.markdown(f"### {title}")
+    st.error(message)
+    if detail and st.checkbox("Show technical details", key=f"err_detail_{hash(title)}"):
+        st.code(detail, language="traceback")
+    if recoverable:
+        st.button("🔄 Retry", on_click=st.rerun, type="primary")
+    else:
+        st.warning("This error is not recoverable. Please restart the app.")
+
+
+def safe_execute(
+    fn: Callable[..., Any],
+    default: Any = None,
+    error_message: str = "Operation failed",
+    logger_name: str | None = None,
+    **kwargs,
+) -> Any:
+    """Execute *fn* with sensible error handling.
+
+    Returns *default* on failure rather than raising.
+    """
+    log = logging.getLogger(logger_name or __name__)
+    try:
+        return fn(**kwargs)
+    except Exception as exc:
+        log.warning("%s: %s", error_message, exc)
+        return default
diff --git a/models/model_init.py b/models/model_init.py
index 656906f..2805c23 100644
--- a/models/model_init.py
+++ b/models/model_init.py
@@ -212,7 +212,7 @@ def display_model_status_ui():
 except Exception as e:
     MODEL_STATUS = False
     MODEL_ERROR_MESSAGE = (
-        f"❌ Critical error during model initialization: {e!s}\n"
+        f"[ERROR] Critical error during model initialization: {e!s}\n"
         "   Please check your Python environment and dependencies."
     )
     MODEL_WARNINGS = []
diff --git a/models/navigation.py b/models/navigation.py
new file mode 100644
index 0000000..4b5534a
--- /dev/null
+++ b/models/navigation.py
@@ -0,0 +1,44 @@
+"""Top navigation bar for page routing."""
+
+import streamlit as st
+
+PAGES = {
+    "home": "🏠 Home",
+    "analyzer": "🔍 SMS Analyzer",
+    "about": "ℹ️ About",
+    "features": "ΓÜí Features",
+    "analytics": "📊 Analytics",
+    "models": "🤖 Models",
+    "feedback": "💬 Feedback",
+    "help": "Γ¥ô Help",
+    "contact": "📞 Contact",
+    "docs": "📚 Docs",
+    "api": "🔌 API",
+    "settings": "⚙️ Settings",
+}
+
+
+def top_navigation_bar(navigate_to):
+    """Render a horizontal navigation bar at the top of the page."""
+    current = st.session_state.get("current_page", "home")
+    cols = st.columns(len(PAGES))
+    for col, (page_key, page_label) in zip(cols, PAGES.items()):
+        with col:
+            is_active = page_key == current
+            if is_active:
+                st.markdown(
+                    f'<div style="text-align:center;padding:6px 0;'
+                    f'background:#00d4aa20;border-radius:8px;'
+                    f'border:1px solid #00d4aa;">'
+                    f'<span style="color:#00d4aa;font-weight:600;font-size:0.85rem;">'
+                    f"{page_label}</span></div>",
+                    unsafe_allow_html=True,
+                )
+            else:
+                if st.button(
+                    page_label,
+                    key=f"nav_top_{page_key}",
+                    use_container_width=True,
+                    help=f"Go to {page_label}",
+                ):
+                    navigate_to(page_key)
diff --git a/page_functions.py b/page_functions.py
index 72d4201..3d36cea 100644
--- a/page_functions.py
+++ b/page_functions.py
@@ -45,6 +45,17 @@ def load_global_styles():
 # Callers must pass it explicitly to show_feedback_page(navigate_to=...).
 
 
+def ui_error_boundary(func):
+    """Decorator to isolate component rendering errors and present recovery UI."""
+    def wrapper(*args, **kwargs):
+        try:
+            return func(*args, **kwargs)
+        except Exception as e:
+            st.error(f"⚠️ A rendering error occurred in this component: {e!s}")
+            if st.button("🔄 Reload Page / Recover UI", key=f"recover_{func.__name__}"):
+                st.rerun()
+    return wrapper
+
 def show_feedback_page(navigate_to):
     """Feedback page for user comments, suggestions, and bug reports"""
     # Import the feedback handler