docs: update API and User Guide with search filters and saved searches

- Document new /api/search endpoint with all filter parameters
- Update saved searches docs with new allowed filter keys
- Update User Guide with search view filters and saved searches usage

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

docs/API.md

@@ -332,10 +332,62 @@ GET /api/files?status=completed&mime_type=application/pdf&tags=invoice&date_from
 
 > **Tip**: Filter state is reflected in query parameters, making URLs shareable as bookmarks or direct links.
 
+### Full-Text Search
+
+**GET** `/api/search`
+
+Search documents by full text across OCR content, titles, filenames, tags, sender, and document type. Powered by Meilisearch.
+
+**Query Parameters**:
+
+| Parameter | Type | Required | Description |
+|-----------|------|----------|-------------|
+| `q` | string | Yes | Full-text search query (1–512 chars) |
+| `mime_type` | string | No | Filter by MIME type (e.g. `application/pdf`) |
+| `document_type` | string | No | Filter by document type (e.g. `Invoice`) |
+| `language` | string | No | Filter by language code (e.g. `de`, `en`) |
+| `tags` | string | No | Filter by tag (exact match on a single tag) |
+| `sender` | string | No | Filter by sender/absender (exact match) |
+| `text_quality` | string | No | Filter by OCR text quality: `no_text`, `low`, `medium`, `high` |
+| `date_from` | int | No | Filter results created after this Unix timestamp |
+| `date_to` | int | No | Filter results created before this Unix timestamp |
+| `page` | int | No | Page number, default: 1 |
+| `per_page` | int | No | Results per page (1–100), default: 20 |
+
+**Example**:
+```
+GET /api/search?q=invoice&document_type=Invoice&tags=amazon&text_quality=high&page=1
+```
+
+**Response**:
+```json
+{
+  "results": [
+    {
+      "file_id": 42,
+      "original_filename": "2026-01-15_Invoice_Amazon.pdf",
+      "document_title": "Amazon Invoice January 2026",
+      "document_type": "Invoice",
+      "tags": ["amazon", "invoice"],
+      "_formatted": {
+        "document_title": "Amazon <mark>Invoice</mark> January 2026",
+        "ocr_text": "...total amount of the <mark>invoice</mark> is..."
+      }
+    }
+  ],
+  "total": 42,
+  "page": 1,
+  "pages": 3,
+  "query": "invoice"
+}
+```
+
 ### Saved Searches
 
 Saved searches allow users to save and reuse filter combinations. Each user can store up to 50 saved searches.
 
+Saved searches are used on both the **Files** page (for file management filters) and the **Search** page (for content-finding filters including full-text queries).
+
 #### List Saved Searches
 
 **GET** `/api/saved-searches`
@@ -349,8 +401,9 @@ Returns all saved searches for the current user.
     "id": 1,
     "name": "Recent Invoices",
     "filters": {
+      "q": "invoice total",
       "tags": "invoice",
-      "status": "completed",
+      "document_type": "Invoice",
       "date_from": "2026-01-01"
     },
     "created_at": "2026-03-01T10:00:00Z",
@@ -368,14 +421,21 @@ Returns all saved searches for the current user.
 {
   "name": "Recent Invoices",
   "filters": {
+    "q": "invoice total",
     "tags": "invoice",
-    "status": "completed",
+    "document_type": "Invoice",
     "date_from": "2026-01-01"
   }
 }
 ```
 
-**Allowed filter keys**: `search`, `mime_type`, `status`, `date_from`, `date_to`, `storage_provider`, `tags`, `sort_by`, `sort_order`
+**Allowed filter keys**:
+
+Files-view keys: `search`, `mime_type`, `status`, `storage_provider`, `sort_by`, `sort_order`
+
+Search-view keys: `q`, `document_type`, `language`, `sender`, `text_quality`
+
+Shared keys: `tags`, `date_from`, `date_to`
 
 **Response** (201 Created): The created saved search object.
 

docs/UserGuide.md

@@ -119,16 +119,35 @@ The **Files** page includes a full-text search bar (labelled "Full-Text Search")
 
 ### Dedicated Search Page
 
-For a more focused search experience, use the **Search** page accessible from the main navigation:
+For a more focused content-finding experience, use the **Search** page accessible from the main navigation:
 
 1. Navigate to the **Search** page
 2. Type your query into the search box — results appear automatically as you type (or press Enter)
-3. Results are displayed in a Google-style format showing:
+3. Use the **content-finding filters** to narrow results:
+   - **Document Type** — e.g. Invoice, Contract
+   - **Tags** — filter by a specific tag
+   - **Sender** — filter by sender / absender
+   - **Language** — filter by ISO language code (e.g. `de`, `en`)
+   - **Text Quality** — filter by OCR text quality (High, Medium, Low, No text)
+   - **Date From / Date To** — restrict results to a date range
+4. Results are displayed in a Google-style format showing:
    - **Document title** (linked to the file detail page)
    - **Filename**
    - **Document type**, **sender**, and **tag** badges
    - **Content preview** with highlighted matching terms
-4. Use pagination to browse through large result sets
+5. Use pagination to browse through large result sets
+
+### Saved Searches
+
+Both the **Files** and **Search** pages support **saved searches** — named filter presets you can create and reuse:
+
+1. Apply your desired filters (and optionally a search query on the Search page)
+2. Click **Save Current** in the saved searches bar
+3. Enter a name for the saved search
+4. Your saved search appears as a clickable tag — click it to instantly re-apply those filters
+5. Click the **×** button next to a saved search to delete it
+
+On the **Search** page, saved searches store the full-text query (`q`) along with all active content-finding filters. On the **Files** page, saved searches store the file management filters (filename search, MIME type, status, etc.).
 
 The search page is also accessible via URL with a pre-filled query: `/search?q=invoice`