fix(ci): replace taplo with azldev for TOML validation

taplo lint was validating TOML files against a static JSON schema that
drifts out of date whenever azldev adds new config fields, causing
spurious CI failures on valid configs.

Replace the Rust/taplo toolchain with azldev, which is the authoritative
parser for these files:

- "azldev config dump -q" validates syntax, schema, includes, and
  full config resolution in strict mode (fails on unknown fields).
- "azldev config generate-schema" + diff ensures the checked-in
  schema stays in sync, with a clear error message if it drifts.

Delete taplo.toml since taplo is no longer used in CI.

Author: christopherco

.github/workflows/lint.yaml

@@ -15,25 +15,31 @@ permissions:
 
 jobs:
   lint:
-    name: "Lint TOML files"
+    name: "Validate TOML config"
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
         uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           persist-credentials: false
-    
-      - name: Set up rust toolchain
-        uses: dtolnay/rust-toolchain@e97e2d8cc328f1b50210efc529dca0028893a2d9 # v1
+
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
         with:
-          toolchain: stable
+          go-version: stable
+          cache: false
 
-      - name: Enable cargo cache
-        uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2.8.2
+      - name: Install azldev
+        run: go install github.com/microsoft/azure-linux-dev-tools/cmd/azldev@main
 
-      - name: "Install linter (taplo)"
-        run: cargo install --locked taplo-cli
+      - name: "Validate config (strict)"
+        run: azldev config dump -q > /dev/null
 
-      - name: "Run linter"
-        run: taplo lint --colors=always
+      - name: "Check schema freshness"
+        run: |
+          azldev config generate-schema > /tmp/azldev.schema.json
+          if ! diff -u external/schemas/azldev.schema.json /tmp/azldev.schema.json; then
+            echo "::error::Checked-in schema is out of date. Run: azldev config generate-schema > external/schemas/azldev.schema.json"
+            exit 1
+          fi