diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 797c69f0..17a35b1c 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -6,7 +6,7 @@
 
 version: 2
 updates:
-  
+
   # Maintain dependencies for GitHub Actions
   - package-ecosystem: "github-actions"
     directory: "/"
diff --git a/.github/workflows/code-metrics.yml b/.github/workflows/code-metrics.yml
index 9e4fbe24..749e2606 100644
--- a/.github/workflows/code-metrics.yml
+++ b/.github/workflows/code-metrics.yml
@@ -50,4 +50,4 @@ jobs:
         with:
           title: '${{ steps.dotnet-code-metrics.outputs.summary-title }}'
           body: '${{ steps.dotnet-code-metrics.outputs.summary-details }}'
-          commit-message: '.NET code metrics, automated pull request.'
\ No newline at end of file
+          commit-message: '.NET code metrics, automated pull request.'
diff --git a/.github/workflows/lint-markdown.yml b/.github/workflows/lint-markdown.yml
new file mode 100644
index 00000000..d03c4004
--- /dev/null
+++ b/.github/workflows/lint-markdown.yml
@@ -0,0 +1,32 @@
+name: Lint Markdown
+# Runs markdownlint-cli2 using the repo's .markdownlint.json config
+
+on:
+  push:
+    branches: [dev, insider]
+    paths: ['**.md', '.markdownlint.json', '.github/workflows/lint-markdown.yml']
+  pull_request:
+    branches: [dev, preview, main, insider]
+    paths: ['**.md', '.markdownlint.json', '.github/workflows/lint-markdown.yml']
+
+permissions:
+  contents: read
+
+jobs:
+  markdownlint:
+    name: markdownlint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Run markdownlint
+        uses: DavidAnson/markdownlint-cli2-action@v23
+        with:
+          globs: |
+            **/*.md
+            !.squad/**
+            !.copilot/**
+            !.github/agents/**
+            !.github/skills/**
+            !.github/copilot-instructions.md
+          config: '.markdownlint.json'
diff --git a/.github/workflows/lint-yaml.yml b/.github/workflows/lint-yaml.yml
new file mode 100644
index 00000000..af66e806
--- /dev/null
+++ b/.github/workflows/lint-yaml.yml
@@ -0,0 +1,38 @@
+name: Lint YAML
+# Validates all workflow and config YAML files
+
+on:
+  push:
+    branches: [dev, insider]
+    paths: ['**.yml', '**.yaml']
+  pull_request:
+    branches: [dev, preview, main, insider]
+    paths: ['**.yml', '**.yaml']
+
+permissions:
+  contents: read
+
+jobs:
+  yamllint:
+    name: yamllint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Run yamllint
+        uses: ibiqlik/action-yamllint@v3
+        with:
+          file_or_dir: .
+          config_data: |
+            extends: default
+            ignore: |
+              .squad/
+            rules:
+              line-length:
+                max: 200
+                allow-non-breakable-inline-mappings: true
+              truthy:
+                allowed-values: ['true', 'false', 'on']
+              brackets:
+                min-spaces-inside: 0
+                max-spaces-inside: 1
diff --git a/.github/workflows/squad-heartbeat.yml b/.github/workflows/squad-heartbeat.yml
index 00b32a1c..6a68a488 100644
--- a/.github/workflows/squad-heartbeat.yml
+++ b/.github/workflows/squad-heartbeat.yml
@@ -61,13 +61,13 @@ jobs:
               core.info('No triage results — board is clear');
               return;
             }
-            
+
             const results = JSON.parse(fs.readFileSync(path, 'utf8'));
             if (results.length === 0) {
               core.info('📋 Board is clear — Ralph found no untriaged issues');
               return;
             }
-            
+
             for (const decision of results) {
               try {
                 await github.rest.issues.addLabels({
@@ -76,7 +76,7 @@ jobs:
                   issue_number: decision.issueNumber,
                   labels: [decision.label]
                 });
-                
+
                 await github.rest.issues.createComment({
                   owner: context.repo.owner,
                   repo: context.repo.repo,
@@ -92,13 +92,13 @@ jobs:
                     '> To reassign, swap the `squad:*` label.'
                   ].join('\n')
                 });
-                
+
                 core.info(`Triaged #${decision.issueNumber} → ${decision.assignTo} (${decision.source})`);
               } catch (e) {
                 core.warning(`Failed to triage #${decision.issueNumber}: ${e.message}`);
               }
             }
-            
+
             core.info(`🔄 Ralph triaged ${results.length} issue(s)`);
 
       # Copilot auto-assign step (uses PAT if available)
diff --git a/.github/workflows/squad-label-enforce.yml b/.github/workflows/squad-label-enforce.yml
index 147ac130..2cc36a93 100644
--- a/.github/workflows/squad-label-enforce.yml
+++ b/.github/workflows/squad-label-enforce.yml
@@ -35,7 +35,7 @@ jobs:
 
             // Handle go: namespace (mutual exclusivity)
             if (appliedLabel.startsWith('go:')) {
-              const otherGoLabels = allLabels.filter(l => 
+              const otherGoLabels = allLabels.filter(l =>
                 l.startsWith('go:') && l !== appliedLabel
               );
 
@@ -97,7 +97,7 @@ jobs:
 
             // Handle release: namespace (mutual exclusivity)
             if (appliedLabel.startsWith('release:')) {
-              const otherReleaseLabels = allLabels.filter(l => 
+              const otherReleaseLabels = allLabels.filter(l =>
                 l.startsWith('release:') && l !== appliedLabel
               );
 
@@ -123,7 +123,7 @@ jobs:
 
             // Handle type: namespace (mutual exclusivity)
             if (appliedLabel.startsWith('type:')) {
-              const otherTypeLabels = allLabels.filter(l => 
+              const otherTypeLabels = allLabels.filter(l =>
                 l.startsWith('type:') && l !== appliedLabel
               );
 
@@ -149,7 +149,7 @@ jobs:
 
             // Handle priority: namespace (mutual exclusivity)
             if (appliedLabel.startsWith('priority:')) {
-              const otherPriorityLabels = allLabels.filter(l => 
+              const otherPriorityLabels = allLabels.filter(l =>
                 l.startsWith('priority:') && l !== appliedLabel
               );
 
diff --git a/.github/workflows/squad-mark-released.yml b/.github/workflows/squad-mark-released.yml
index 7b5b6abc..32138f26 100644
--- a/.github/workflows/squad-mark-released.yml
+++ b/.github/workflows/squad-mark-released.yml
@@ -13,9 +13,9 @@ permissions:
   contents: read
 
 env:
-  PROJECT_ID:        PVT_kwHOA5k0b84BVFTy
-  STATUS_FIELD_ID:   PVTSSF_lAHOA5k0b84BVFTyzhQjgPk
-  DONE_OPTION_ID:    "98236657"
+  PROJECT_ID: PVT_kwHOA5k0b84BVFTy
+  STATUS_FIELD_ID: PVTSSF_lAHOA5k0b84BVFTyzhQjgPk
+  DONE_OPTION_ID: "98236657"
   RELEASED_OPTION_ID: "8e246b27"
 
 jobs:
diff --git a/.github/workflows/squad-pr-auto-label.yml b/.github/workflows/squad-pr-auto-label.yml
index c0ff06fe..c918e541 100644
--- a/.github/workflows/squad-pr-auto-label.yml
+++ b/.github/workflows/squad-pr-auto-label.yml
@@ -30,7 +30,7 @@ jobs:
             const labelNames = currentLabels.map(l => l.name);
 
             // Check if already has squad labels
-            const hasSquadLabel = labelNames.some(name => 
+            const hasSquadLabel = labelNames.some(name =>
               name === 'squad' || name.startsWith('squad:')
             );
 
diff --git a/.github/workflows/squad-test.yml b/.github/workflows/squad-test.yml
index 754fe33d..37cfd710 100644
--- a/.github/workflows/squad-test.yml
+++ b/.github/workflows/squad-test.yml
@@ -462,7 +462,7 @@ jobs:
           ls -la ~/.cache/ms-playwright/ 2>/dev/null || echo "No playwright cache found"
           echo "dotnet version:"
           dotnet --version
-          
+
           dotnet test tests/AppHost.Tests \
             --configuration Release \
             --no-build \