FRE-4661: Implement ShieldAI PR workflow recommendations

- Add Gitea PR template with code review checklist
- Add CODEOWNERS file for review assignment policy
- Update shieldai-workflow.md with implemented workflow
- Add branch-protection-rules.yaml for gt/master protection

Co-Authored-By: Paperclip <noreply@paperclip.ing>

shared/branch-protection-rules.yaml

@@ -0,0 +1,71 @@
+# Branch Protection Rules for FrenoCorp Repository
+# Apply via Gitea web UI: Repository Settings > Branches > Protect Branch
+# Or via Gitea API: PUT /repos/{owner}/{repo}/branches/{branch}/protection
+
+branch: gt/master
+settings:
+  protected: true
+  push:
+    enforced_users: []
+    excluded_users: []
+    block_pushes: false
+    only_allow_whitelist: false
+  protection:
+    enforce_branch_name: false
+    strict_history:
+      strict: false
+      allowed_types: []
+      discrete_bytes_enabled: false
+      block_out_of_order_files: false
+  pull_request:
+    strict_approvals:
+      strict: false
+      dismiss_stale: false
+      approval_labels: []
+    required_approvals: 1
+    required_reviewer_amount: 0
+    dismiss_pr_merge: true
+    automergetype: 1
+    auto_merge_allowed_user: []
+    auto_merge_allowed_team: []
+  status:
+    strict_status:
+      strict: false
+      contexts:
+        - lint
+        - typecheck
+        - test
+      min_runs: 0
+      max_build_pending: 0
+      max_build_pending_user: []
+      max_build_pending_team: []
+    strict_branches:
+      strict: false
+      branches: []
+  assignee:
+    enforce_assignee: false
+    total_assignees: 0
+  administrator:
+    enforce_admins: false
+  push_force:
+    allow_force_push: true
+    force_push_roles:
+      owner: true
+      maintainer: true
+  push_merge:
+    allow_merge_commits: true
+    allow_squash_merge: true
+    allow_rebase: true
+    allow_rebase_expanded: true
+    allow_ff: true
+    allow_ff_only: false
+    default_merge_style: 1
+    merge_title: 0
+    merge_content_body: 0
+  file_extension:
+    blocked_extensions: []
+  max_unchanged_commits: 0
+  max_file_size: 0
+  max_changed_files: 0
+  max_filediff_size: 0
+  max_diff_files_to_stat: 0