Remove stray .snap.new filtering from schema fixtures reader

Motivation:
- `codex-app-server-protocol` schema fixtures are not insta snapshots.
- Filtering `*.snap.new` is confusing and risks hiding real files.

What changed:
- Remove the `.snap.new` filename special case in `read_schema_fixture_tree`.

Refs: macOS Bazel schema fixture mismatch investigation

codex-rs/app-server-protocol/schema/json/v1/ForkConversationParams.json

@@ -0,0 +1,159 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "definitions": {
+    "AskForApproval": {
+      "description": "Determines the conditions under which the user is consulted to approve running the command proposed by Codex.",
+      "oneOf": [
+        {
+          "description": "Under this policy, only \"known safe\" commands—as determined by `is_safe_command()`—that **only read files** are auto‑approved. Everything else will ask the user to approve.",
+          "enum": [
+            "untrusted"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "*All* commands are auto‑approved, but they are expected to run inside a sandbox where network access is disabled and writes are confined to a specific set of paths. If the command fails, it will be escalated to the user to approve execution without a sandbox.",
+          "enum": [
+            "on-failure"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "The model decides when to ask the user for approval.",
+          "enum": [
+            "on-request"
+          ],
+          "type": "string"
+        },
+        {
+          "description": "Never ask the user to approve commands. Failures are immediately returned to the model, and never escalated to the user for approval.",
+          "enum": [
+            "never"
+          ],
+          "type": "string"
+        }
+      ]
+    },
+    "NewConversationParams": {
+      "properties": {
+        "approvalPolicy": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/AskForApproval"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
+        "baseInstructions": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "compactPrompt": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "config": {
+          "additionalProperties": true,
+          "type": [
+            "object",
+            "null"
+          ]
+        },
+        "cwd": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "developerInstructions": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "includeApplyPatchTool": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
+        "model": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "modelProvider": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "profile": {
+          "type": [
+            "string",
+            "null"
+          ]
+        },
+        "sandbox": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/SandboxMode"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        }
+      },
+      "type": "object"
+    },
+    "SandboxMode": {
+      "enum": [
+        "read-only",
+        "workspace-write",
+        "danger-full-access"
+      ],
+      "type": "string"
+    },
+    "ThreadId": {
+      "type": "string"
+    }
+  },
+  "properties": {
+    "conversationId": {
+      "anyOf": [
+        {
+          "$ref": "#/definitions/ThreadId"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "overrides": {
+      "anyOf": [
+        {
+          "$ref": "#/definitions/NewConversationParams"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "path": {
+      "type": [
+        "string",
+        "null"
+      ]
+    }
+  },
+  "title": "ForkConversationParams",
+  "type": "object"
+}