feat(urlpattern): add WHATWG URLPattern support

Implement WHATWG-style URLPattern parsing, compilation, matching,
generation, and component comparison with cache-backed reuse.

Integrate matched params with AsyncContext and initialize the shared
URLPattern params variable at application boot so route context stays
stable across processes.

Regroup normalize_component_input/2 clauses to remove the compiler
warning, add defensive coverage for URLPattern edge cases, and
document the new API in the README and changelog.

Author: sntran

CHANGELOG.md

@@ -8,6 +8,11 @@ All notable changes to this project are documented in this file.
 
 - `Web.File`.
 - `Web.FormData` struct and streaming multipart parser.
+- `Web.URLPattern` with WHATWG-style pattern parsing, compilation, matching,
+  generation, component comparison, and ambient route param injection via
+  `match_context/3`.
+- `Web.URLPattern.Cache`, `Web.URLPattern.Parser`, and
+  `Web.URLPattern.Compiler`.
 - `Web.AsyncContext` for BEAM-native async context propagation.
 - `Web.AsyncContext.Variable` for scoped context values that participate in
   snapshot capture and restoration.
@@ -48,6 +53,9 @@ All notable changes to this project are documented in this file.
 - `Web.FormData.Parser` now captures and restores `Web.AsyncContext`
   snapshots, auto-binds to ambient abort signals, and propagates that context
   into live file streams it creates on demand.
+- `Web.Application` now eagerly initializes the singleton
+  `Web.URLPattern.params/0` variable during boot so route-param context stays
+  stable across processes in async workloads and tests.
 - `Web.Console.group/1` now keeps `group_depth` in logger metadata so grouped
   output survives async-context snapshot restore across task boundaries.
 - `Web.CompressionStream` and `Web.DecompressionStream` now emit context-aware

README.md

@@ -124,6 +124,35 @@ end)
 # => ["req-42"]
 ```
 
+### `Web.URLPattern` — Spec-Compliant Routing and URL Matching
+`Web.URLPattern` implements the WHATWG URLPattern API for matching URL strings,
+`Web.URL` structs, requests, or component maps. It also bridges naturally into
+`Web.AsyncContext`, so successful matches can expose captured params to
+downstream work with `match_context/3`.
+
+```elixir
+use Web
+
+pattern =
+  URLPattern.new(%{
+    protocol: "https",
+    hostname: "example.com",
+    pathname: "/users/:id"
+  })
+
+URLPattern.test(pattern, "https://example.com/users/42")
+# => true
+
+result = URLPattern.exec(pattern, "https://example.com/users/42")
+result[:pathname][:groups]
+# => %{"id" => "42"}
+
+URLPattern.match_context(pattern, "https://example.com/users/42", fn ->
+  AsyncContext.Variable.get(URLPattern.params())
+end)
+# => %{"id" => "42"}
+```
+
 ---
 
 ## 📖 API Usage & Examples

coveralls.json

@@ -0,0 +1,5 @@
+{
+  "skip_files": [
+    "test/support/wpt.ex"
+  ]
+}

lib/web/application.ex

@@ -7,8 +7,14 @@ defmodule Web.Application do
   def start(_type, _args) do
     Web.Performance.put_time_origin()
 
+    # Eagerly initialize the url_params singleton in :persistent_term so that
+    # the Variable handle is stable across all processes from the moment the
+    # application boots.
+    Web.URLPattern.params()
+
     children = [
       {Task.Supervisor, name: Web.TaskSupervisor},
+      Web.URLPattern.Cache,
       {Finch,
        name: Web.Finch,
        pools: %{