fix(ui): prevent search input from clearing on each keystroke and add dedicated /search page

The debounceSearch() function in files.html called clearFullTextSearch()
when the query was shorter than 2 characters. Since clearFullTextSearch()
sets input.value = '', every single keystroke was immediately erased —
users could paste text but not type.

Fix: debounceSearch now only hides the results panel for short queries
without touching the input value.

Also adds a dedicated /search page with Google-style results showing
content previews (document title, filename, type badges, tag badges,
sender, and OCR text snippets with highlighted matches).

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

tests/test_views_search.py

@@ -0,0 +1,41 @@
+"""Tests for the dedicated search page view (app/views/search.py)."""
+
+import pytest
+
+
+@pytest.mark.unit
+class TestSearchPage:
+    """Tests for GET /search view endpoint."""
+
+    def test_search_page_renders(self, client):
+        """GET /search returns 200 with search template."""
+        response = client.get("/search")
+        assert response.status_code == 200
+        assert "Document Search" in response.text
+
+    def test_search_page_with_query(self, client):
+        """GET /search?q=invoice pre-fills the search input."""
+        response = client.get("/search?q=invoice")
+        assert response.status_code == 200
+        assert 'value="invoice"' in response.text
+
+    def test_search_page_empty_query(self, client):
+        """GET /search?q= renders page without error."""
+        response = client.get("/search?q=")
+        assert response.status_code == 200
+        assert "Document Search" in response.text
+
+    def test_search_page_contains_search_elements(self, client):
+        """GET /search contains required search UI elements."""
+        response = client.get("/search")
+        assert response.status_code == 200
+        assert 'id="search-input"' in response.text
+        assert 'id="search-btn"' in response.text
+        assert 'id="search-results"' in response.text
+        assert "/api/search" in response.text
+
+    def test_search_page_query_too_long(self, client):
+        """GET /search?q=<very long> returns 422 for exceeding max_length."""
+        long_query = "a" * 600
+        response = client.get(f"/search?q={long_query}")
+        assert response.status_code == 422