Add assetlinks.json to link android app to app.khoj.dev domain

Add sha cert of android upload, signing keys to open debug, prod apps
as TWA in fullscreen on android phones

src/khoj/interface/web/.well-known/assetlinks.json

@@ -0,0 +1,11 @@
+[{
+ "relation": ["delegate_permission/common.handle_all_urls"],
+ "target": {
+   "namespace": "android_app",
+   "package_name": "dev.khoj.app",
+    "sha256_cert_fingerprints": [
+      "CC:98:4A:0A:F1:CC:84:26:AC:02:86:49:AA:69:64:B9:5E:63:A3:EF:18:56:EA:CA:13:C1:3A:15:CA:49:77:46",
+      "D4:5A:6F:6C:18:28:D2:1C:78:27:92:C6:AC:DB:4C:12:C4:52:A1:88:9B:A1:F5:67:D1:22:FE:A0:0F:B1:AE:92"
+    ]
+ }
+}]

src/khoj/routers/web_client.py

@@ -134,3 +134,8 @@ def automations_config_page(
             "request": request,
         },
     )
+
+
+@web_client.get("/.well-known/assetlinks.json", response_class=FileResponse)
+def assetlinks(request: Request):
+    return FileResponse(constants.assetlinks_file_path)

src/khoj/utils/constants.py

@@ -5,6 +5,7 @@ app_root_directory = Path(__file__).parent.parent.parent
 web_directory = app_root_directory / "khoj/interface/web/"
 next_js_directory = app_root_directory / "khoj/interface/built/"
 pypi_static_directory = app_root_directory / "khoj/interface/compiled/"
+assetlinks_file_path = web_directory / ".well-known/assetlinks.json"
 empty_escape_sequences = "\n|\r|\t| "
 app_env_filepath = "~/.khoj/env"
 telemetry_server = "https://khoj.beta.haletic.com/v1/telemetry"