Add 'params' frame-local injection

Mirrors the 'route' injection: hooks can do ->inject('params') to receive
the resolved path params (array<string, string>) for the current dispatch
frame. Skips shared context for the same reason 'route' does — nested
execute() calls (sub-request dispatch) can't trample each other.

Refactor: collapse the per-name special-cases into a frame-local map for
clarity. Both 'route' and 'params' come from the dispatch frame; the map
makes that explicit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: loks0n

src/Http/Http.php

@@ -720,15 +720,18 @@ protected function getArguments(Hook $hook, array $values, array $requestParams,
             $arguments[$param['order']] = $value;
         }
 
-        foreach ($hook->getInjections() as $injection) {
-            // 'route' is frame-local: pass the dispatch frame's matched Route
-            // through directly instead of routing through shared context.
-            if ($injection['name'] === 'route') {
-                $arguments[$injection['order']] = $route;
-                continue;
-            }
+        // Frame-local injections come from the dispatch frame, not the
+        // per-request context. Writing them to context would leak across
+        // nested execute() calls (e.g. sub-request dispatch).
+        $frameLocals = [
+            'route' => $route,
+            'params' => $values,
+        ];
 
-            $arguments[$injection['order']] = $this->adapter->context()->get($injection['name']);
+        foreach ($hook->getInjections() as $injection) {
+            $arguments[$injection['order']] = \array_key_exists($injection['name'], $frameLocals)
+                ? $frameLocals[$injection['name']]
+                : $this->adapter->context()->get($injection['name']);
         }
 
         return $arguments;

tests/HttpTest.php

@@ -741,6 +741,42 @@ public function testSubrequestRestoresOuterRoute(): void
         $this->assertSame(['/inner', '/outer'], $captured);
     }
 
+    public function testParamsInjection(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+        $_SERVER['REQUEST_URI'] = '/users/abc-123/posts/42';
+
+        $captured = null;
+
+        Http::get('/users/:id/posts/:postId')
+            ->inject('params')
+            ->action(function (array $params) use (&$captured) {
+                $captured = $params;
+            });
+
+        $this->http->execute(new Request(), new Response());
+
+        $this->assertSame(['id' => 'abc-123', 'postId' => '42'], $captured);
+    }
+
+    public function testParamsInjectionEmptyForStaticRoute(): void
+    {
+        $_SERVER['REQUEST_METHOD'] = 'GET';
+        $_SERVER['REQUEST_URI'] = '/static';
+
+        $captured = null;
+
+        Http::get('/static')
+            ->inject('params')
+            ->action(function (array $params) use (&$captured) {
+                $captured = $params;
+            });
+
+        $this->http->execute(new Request(), new Response());
+
+        $this->assertSame([], $captured);
+    }
+
     public function testWildcardRoute(): void
     {
         $method = $_SERVER['REQUEST_METHOD'] ?? null;