feat(ci): integrate reusable CI workflows from supabase/actions (#1299)

* feat(ci): integrate reusable CI workflows from supabase/actions

Adds three reusable workflows to standardize CI processes:
- block-merge: Prevents merging of WIP/draft PRs and those with do-not-merge labels
- stale: Automates management of inactive issues (180 days) and PRs (90 days)
- label-issues: Auto-labels issues and PRs based on module scope from conventional commits

These workflows align with the CI patterns used across other Supabase client libraries (supabase-swift, supabase-js) and reduce maintenance burden through shared workflow definitions.

Closes SDK-624

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* ci: use full commit sha hash for reusable actions

---------

Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: grdsdev

.github/workflows/block-merge.yml

@@ -0,0 +1,19 @@
+name: Block WIP/Draft Merges
+
+on:
+  pull_request:
+    types:
+      - opened
+      - edited
+      - synchronize
+      - reopened
+      - ready_for_review
+      - labeled
+      - unlabeled
+
+jobs:
+  block-merge:
+    uses: supabase/actions/.github/workflows/block-merge.yml@659b3cd74a64ee2f1ca0a527922f134707e54671
+    with:
+      block_labels: "do-not-merge,blocked"
+      block_keywords: "wip,do not merge"

.github/workflows/label-issues.yml

@@ -0,0 +1,31 @@
+name: Auto-Label Issues and PRs
+
+on:
+  pull_request:
+    types:
+      - opened
+      - edited
+  issues:
+    types:
+      - opened
+      - edited
+
+jobs:
+  label:
+    uses: supabase/actions/.github/workflows/label-issues.yml@659b3cd74a64ee2f1ca0a527922f134707e54671
+    with:
+      label_mappings: |
+        {
+          "gotrue": "auth",
+          "auth": "auth",
+          "storage": "storage",
+          "storage_client": "storage",
+          "realtime": "realtime",
+          "realtime_client": "realtime",
+          "postgrest": "postgrest",
+          "functions": "functions",
+          "functions_client": "functions",
+          "auth_ui": "auth-ui",
+          "supabase": "supabase",
+          "supabase_flutter": "supabase_flutter"
+        }

.github/workflows/stale.yml

@@ -0,0 +1,19 @@
+name: Manage Stale Issues and PRs
+
+on:
+  schedule:
+    # Run every Sunday at 00:00 UTC
+    - cron: "0 0 * * 0"
+  workflow_dispatch:
+
+jobs:
+  stale:
+    uses: supabase/actions/.github/workflows/stale.yml@659b3cd74a64ee2f1ca0a527922f134707e54671
+    with:
+      days_before_issue_stale: 180
+      days_before_issue_close: 30
+      days_before_pr_stale: 90
+      days_before_pr_close: 14
+      exempt_issue_labels: "priority,security,planned,good first issue"
+      exempt_pr_labels: "priority,security"
+      operations_per_run: 100