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drifts out of date whenever azldev adds new config fields, causing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" validates syntax, schema,
includes, and full config resolution in strict mode (fails on unknown
fields). Errors are printed to stderr for CI diagnostics.

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

Author: christopherco

.github/workflows/lint.yaml

@@ -15,25 +15,23 @@ 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
-        with:
-          toolchain: stable
 
-      - name: Enable cargo cache
-        uses: Swatinem/rust-cache@779680da715d629ac1d338a641029a2f4372abb5 # v2.8.2
+      - name: Set up Go
+        uses: actions/setup-go@d35c59abb061a4a6fb18e82ac0862c26744d6ab5 # v5.5.0
+        with:
+          go-version: stable
+          cache: false
 
-      - name: "Install linter (taplo)"
-        run: cargo install --locked taplo-cli
+      - name: Install azldev
+        run: go install github.com/microsoft/azure-linux-dev-tools/cmd/azldev@0590d38b32c0a414e0969e85aca8542c3d339079
 
-      - name: "Run linter"
-        run: taplo lint --colors=always
+      - name: "Validate config (strict)"
+        run: azldev config dump > /dev/null