feat: add merge_all_wren utility, strutil demo, and 7 new API manual pages

Add WrenFileReader class in apps/merge_all_wren.wren for recursive .wren file discovery and content printing. Introduce example/strutil_demo.wren demonstrating case conversion, hex encoding, SHA256 hashing, string repetition, padding, HTML/JSON escaping, and URL encoding/decoding. Create manual/api pages for argparse, dataset, html, markdown, uuid, wdantic, and web modules. Update manual/api/index.html sidebar and module count from 21 to 28, adding links and cards for the new modules.

test/web/view.wren

@@ -0,0 +1,58 @@
+// retoor <retoor@molodetz.nl>
+
+import "web" for View, Response, Request
+
+class TestView is View {
+    construct new() {}
+
+    get(request) {
+        return Response.json({"method": "GET"})
+    }
+
+    post(request) {
+        return Response.json({"method": "POST"})
+    }
+
+    put(request) {
+        return Response.json({"method": "PUT"})
+    }
+
+    delete(request) {
+        return Response.json({"method": "DELETE"})
+    }
+}
+
+class GetOnlyView is View {
+    construct new() {}
+
+    get(request) {
+        return Response.text("GET only")
+    }
+}
+
+var mockGet = Request.new_("GET", "/test", {}, {}, "", {}, null)
+var mockPost = Request.new_("POST", "/test", {}, {}, "", {}, null)
+var mockPut = Request.new_("PUT", "/test", {}, {}, "", {}, null)
+var mockDelete = Request.new_("DELETE", "/test", {}, {}, "", {}, null)
+var mockPatch = Request.new_("PATCH", "/test", {}, {}, "", {}, null)
+
+var view = TestView.new()
+
+var r1 = view.dispatch(mockGet)
+System.print(r1.body.contains("GET")) // expect: true
+
+var r2 = view.dispatch(mockPost)
+System.print(r2.body.contains("POST")) // expect: true
+
+var r3 = view.dispatch(mockPut)
+System.print(r3.body.contains("PUT")) // expect: true
+
+var r4 = view.dispatch(mockDelete)
+System.print(r4.body.contains("DELETE")) // expect: true
+
+var getOnlyView = GetOnlyView.new()
+var r5 = getOnlyView.dispatch(mockGet)
+System.print(r5.body) // expect: GET only
+
+var r6 = getOnlyView.dispatch(mockPost)
+System.print(r6.status) // expect: 405