fix: compile gh-aw workflows and fix frontmatter errors

- Fix create-pull-request: base → base-branch (correct field name)
- Fix push-to-pull-request-branch: target "created" → "*" with
  title-prefix and labels constraints
- Remove edit: paths (not a valid property); use bare edit:
- Remove web-search tool (not supported by copilot engine)
- Compile both workflows with gh aw v0.68.1 (0 errors, 0 warnings)
- Add .lock.yml files, .github/aw/actions-lock.json, .gitattributes

Author: zircote

.gitattributes

@@ -0,0 +1 @@
+.github/workflows/*.lock.yml linguist-generated=true merge=ours

.github/aw/actions-lock.json

@@ -0,0 +1,14 @@
+{
+  "entries": {
+    "actions/github-script@v9": {
+      "repo": "actions/github-script",
+      "version": "v9",
+      "sha": "373c709c69115d41ff229c7e5df9f8788daa9553"
+    },
+    "github/gh-aw-actions/setup@v0.68.1": {
+      "repo": "github/gh-aw-actions/setup",
+      "version": "v0.68.1",
+      "sha": "2fe53acc038ba01c3bbdc767d4b25df31ca5bdfc"
+    }
+  }
+}