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>

app/views/search.py

@@ -0,0 +1,38 @@
+"""
+Search view for dedicated full-text document search page.
+
+Provides a Google-style search experience with content previews,
+powered by Meilisearch via the existing ``/api/search`` backend.
+"""
+
+import logging
+from typing import Optional
+
+from fastapi import Query, Request
+
+from app.views.base import APIRouter, require_login, templates
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+@router.get("/search")
+@require_login
+def search_page(
+    request: Request,
+    q: Optional[str] = Query(None, max_length=512, description="Full-text search query"),
+):
+    """Render the dedicated search page.
+
+    The page loads with an empty search box (or pre-filled when *q* is given).
+    Actual searching is performed client-side via ``fetch('/api/search')`` so
+    that results stream in without a full page reload.
+    """
+    return templates.TemplateResponse(
+        "search.html",
+        {
+            "request": request,
+            "query": q or "",
+        },
+    )