Add emmylua lua lint CI check

Same setup as established in ExpCluster, emmylua_check with factorio
typedefs generated by fmtk luals-addon. The moduleMap resolves
modules/clusterio and modules/<plugin> requires to their source under
packages/host and plugins, and the mod scaffolding under
packages/host/lua to bare sibling requires.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.emmyrc.json

@@ -0,0 +1,48 @@
+{
+    "$schema": "https://raw.githubusercontent.com/EmmyLuaLs/emmylua-analyzer-rust/refs/heads/main/crates/emmylua_code_analysis/resources/schema.json",
+    "runtime": {
+        "version": "Lua5.2",
+        "requirePattern": [ "?", "?.lua" ]
+    },
+    "workspace": {
+        "$comment-moduleMap": "Rewrites each file's own module path rather than the require string",
+        "$comment-library": "The factorio typedefs are provided by a second config, generated with fmtk luals-addon in ci",
+        "$comment-templates": "The create templates contain __plugin_name__ placeholders and are not valid lua",
+        "ignoreGlobs": [
+            "**/node_modules/**",
+            "**/dist/**",
+            "database/**",
+            "docs/**",
+            "external_plugins/**",
+            "factorio/**",
+            "instances/**",
+            "logs/**",
+            "mods/**",
+            "modules/**",
+            "temp/**",
+            "packages/create/templates/**"
+        ],
+        "moduleMap": [
+            { "pattern": "^packages\\.host\\.modules\\.(.+)$", "replace": "modules.$1" },
+            { "pattern": "^plugins\\.([^.]+)\\.module\\.(.+)$", "replace": "modules.$1.$2" },
+            { "pattern": "^packages\\.host\\.lua\\.export\\.(.+)$", "replace": "$1" },
+            { "pattern": "^packages\\.host\\.lua\\.clusterio_lib\\.(.+)$", "replace": "$1" }
+        ]
+    },
+    "doc": {
+        "privateName": [ "__*" ]
+    },
+    "$comment-disable": "Same set as ExpCluster, these are editor level hints rather than ci checks",
+    "$comment-unnecessary-if": "Disabled by the config fmtk generates for itself, the api union types make it unreliable",
+    "diagnostics": {
+        "globals": [ "__DebugAdapter", "__Profiler" ],
+        "disable": [
+            "assign-type-mismatch",
+            "param-type-mismatch",
+            "preferred-local-alias",
+            "unnecessary-assert",
+            "unnecessary-if",
+            "unused"
+        ]
+    }
+}

.github/workflows/lua-lint.yml

@@ -0,0 +1,83 @@
+name: Lua Lint
+
+on:
+  push:
+  pull_request:
+
+env:
+  EMMYLUA_CHECK_VERSION: "0.24.0"
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: lts/*
+      - name: Generate Factorio typedefs
+        run: |
+          npm install --prefix "$RUNNER_TEMP/fmtk" factoriomod-debug
+          "$RUNNER_TEMP/fmtk/node_modules/.bin/fmtk" luals-addon "$RUNNER_TEMP"
+      - name: Install emmylua_check
+        run: |
+          curl -fsSL "https://github.com/EmmyLuaLs/emmylua-analyzer-rust/releases/download/${EMMYLUA_CHECK_VERSION}/emmylua_check-linux-x64.tar.gz" \
+            | tar -xz -C "$RUNNER_TEMP"
+      - name: Run Lint Report
+        shell: bash
+        run: |
+          # The typedefs are generated per run, so their path is passed via a second config
+          jq -n --arg lib "$RUNNER_TEMP/factorio/library" \
+            '{ workspace: { library: [ $lib ] } }' \
+            > "$RUNNER_TEMP/ci.emmyrc.json"
+
+          # Exits non zero on error severity, so the gate below is used instead
+          "$RUNNER_TEMP/emmylua_check" . --config ".emmyrc.json,$RUNNER_TEMP/ci.emmyrc.json" \
+            --output-format json --output check.json || true
+
+          # Credit to https://github.com/Krealle/luals-check-action/blob/main/action.yml
+          # Although some minor fixes were needed
+
+          # Format and print the messages (would be nice to format as a table, but that's too complex for jq)
+          jq -r --arg root "$PWD/" \
+            '.[] | (.file | ltrimstr($root)) as $file | .diagnostics[] |
+              {
+                file: $file,
+                code: .code,
+                line: .range.start.line,
+                message: (.message | split("\n")
+                  | map(if startswith("- ") then .[2:] else . end)
+                  | join("\n")),
+                severity: (if .severity <= 1 then "ERR" else "WARN" end)
+              } |
+              "**[\(.severity)] \(.code):** \(.file)#L\(.line + 1)<br><code>\(.message)</code>"' \
+            check.json > "$GITHUB_STEP_SUMMARY"
+
+          echo ""
+
+          # Github Annotations (limited to 10)
+          jq -r --arg root "$PWD/" \
+            '.[] | (.file | ltrimstr($root)) as $file | .diagnostics[] |
+              {
+                file: $file,
+                title: .code,
+                line: .range.start.line,
+                endLine: .range.end.line,
+                col: .range.start.character,
+                endColumn: .range.end.character,
+                message: (.message | gsub("\n"; "%0A"; "m")),
+                level: (if .severity <= 1 then "error" else "warning" end)
+              } |
+              "::\(.level) file=\(.file),line=\(.line + 1),endLine=\(.endLine + 1),col=\(.col + 1),endColumn=\(.endColumn + 1),title=\(.title)::\(.message) (\(.title))"' \
+            check.json
+
+          # An entry is emitted for every file checked, including clean ones, so
+          # the gate counts diagnostics and asserts the workspace was actually read
+          if [[ $(jq 'length' check.json) -lt 20 ]] ; then
+            echo "::error::Only $(jq 'length' check.json) files were checked, expected the whole workspace"
+            exit 1
+          elif [[ $(jq '[.[].diagnostics[]] | length' check.json) -gt 0 ]] ; then
+            exit 1
+          else
+            echo "✅ All checks succeeded!" | tee "$GITHUB_STEP_SUMMARY"
+          fi