ci(workflows): consolidate policy and rust workflow setup (#564)

* fix(workflows): standardize runner configuration for security jobs

* ci(actionlint): add Blacksmith runner label to config

Add blacksmith-2vcpu-ubuntu-2404 to actionlint self-hosted-runner labels config
to suppress "unknown label" warnings during workflow linting.

This label is used across all workflows after the Blacksmith migration.

* fix(actionlint): adjust indentation for self-hosted runner labels

* feat(security): enhance security workflow with CodeQL analysis steps

* fix(security): update CodeQL action to version 4 for improved analysis

* fix(security): remove duplicate permissions in security workflow

* fix(security): revert CodeQL action to v3 for stability

The v4 version was causing workflow file validation failures.
Reverting to proven v3 version that is working on main branch.

* fix(security): remove duplicate permissions causing workflow validation failure

The permissions block had duplicate security-events and actions keys,
which caused YAML validation errors and prevented workflow execution.

Fixes: workflow file validation failures on main branch

* fix(security): remove pull_request trigger to reduce costs

* fix(security): restore PR trigger but skip codeql on PRs

* fix(security): resolve YAML syntax error in security workflow

* refactor(security): split CodeQL into dedicated scheduled workflow

* fix(security): update workflow name to Rust Package Security Audit

* fix(codeql): remove push trigger, keep schedule and on-demand only

* feat(codeql): add CodeQL configuration file to ignore specific paths

* Potential fix for code scanning alert no. 39: Hard-coded cryptographic value

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

* fix(ci): resolve auto-response workflow merge markers

* fix(build): restore ChannelMessage reply_target usage

* ci(workflows): run workflow sanity on workflow pushes for all branches

* ci(workflows): rename auto-response workflow to PR Auto Responder

* ci(workflows): require owner approval for workflow file changes

* ci: add lint-first PR feedback gate

* ci(workflows): split label policy checks from workflow sanity

* ci(workflows): consolidate policy and rust workflow setup

---------

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

.github/label-policy.json

@@ -0,0 +1,21 @@
+{
+  "contributor_tier_color": "2ED9FF",
+  "contributor_tiers": [
+    {
+      "label": "distinguished contributor",
+      "min_merged_prs": 50
+    },
+    {
+      "label": "principal contributor",
+      "min_merged_prs": 20
+    },
+    {
+      "label": "experienced contributor",
+      "min_merged_prs": 10
+    },
+    {
+      "label": "trusted contributor",
+      "min_merged_prs": 5
+    }
+  ]
+}