feat(theme): dark variant

editors/vscode-prototype/README.md

@@ -13,9 +13,9 @@ integration tests, and they run without npm install, Vivado, xsim, or
 hardware.  A limited opt-in Extension Host runtime smoke exists for local
 dependency-policy review; it is not a product claim.
 
-The package includes a copied pccx aperture-mark icon and a light
-`pccx SystemVerilog Light` color theme derived from the local
-`pccx-UI/Systemverilog-IDE` design-system package.  These assets are
+The package includes a copied pccx aperture-mark icon and
+`pccx SystemVerilog Light` / `pccx SystemVerilog Dark` color themes derived
+from the local `pccx-UI/Systemverilog-IDE` design-system package.  These assets are
 visual branding only; they do not replace the host-theme-first
 presentation boundary and do not make the theme surface complete.
 
@@ -154,9 +154,13 @@ The contributed commands are:
 - `pccxSystemVerilog.showPccxLabBackendStatus`
 - `pccxSystemVerilog.showDiagnosticsHandoffSummary`
 
-The contributed color theme is:
+The contributed color themes are:
 
 - `pccx SystemVerilog Light`
+- `pccx SystemVerilog Dark`
+
+Light/dark maintenance expectations are documented in
+[`docs/theme-consistency.md`](./docs/theme-consistency.md).
 
 The extension icon is `assets/logo/aperture-mark-128.png`, with source
 SVG logo assets retained under `assets/logo/`.  The copied-asset notice is

editors/vscode-prototype/docs/theme-consistency.md

@@ -0,0 +1,97 @@
+# Theme Consistency Rules
+
+The VS Code prototype contributes paired local themes:
+`pccx SystemVerilog Light` and `pccx SystemVerilog Dark`.  The light theme
+comes from the pccx-UI integration work and the dark theme is its follow-up
+variant.  Keep them reviewed as one pair so the dark theme stays a contrast
+variant of the same SystemVerilog editor surface, not a separate design
+system.
+
+This document is a maintenance rule set for:
+
+- `../themes/pccx-systemverilog-light-color-theme.json`
+- `../themes/pccx-systemverilog-dark-color-theme.json`
+- the `contributes.themes` entries in `../package.json`
+
+It does not make the prototype marketplace-ready, LSP-backed, or a complete
+custom theme engine.  The presentation policy remains host-theme-first for
+runtime UI records and future webview-like surfaces.
+
+## Pairing Rules
+
+- Both theme files must keep `semanticHighlighting: true`.
+- Both theme files must keep the same top-level shape: `name`, `type`,
+  `semanticHighlighting`, `colors`, and `tokenColors`.
+- `package.json` must contribute both themes together.  The light entry uses
+  `uiTheme: "vs"` and the dark entry uses `uiTheme: "vs-dark"`.
+- The `colors` maps should keep the same VS Code color keys unless a key is
+  demonstrably unavailable or inappropriate for one theme.  Any exception
+  should be documented in this file or the adjacent review notes.
+- The `tokenColors` arrays must keep the same bucket names, bucket order, and
+  scope lists.  Only foreground values should differ between light and dark.
+- Shared SystemVerilog token buckets are comments, keywords, types,
+  identifiers, literals, diagnostics/invalid tokens, and source default.
+- Shared workbench surface groups are activity bar, title bar, command center,
+  editor, gutter, side bar, list, panel, tabs, status bar, notifications,
+  quick input, terminal, and text links.
+
+## Shared Semantic Roles
+
+Use the same semantic role when choosing different light and dark values.
+
+| Role | Light rule | Dark rule |
+| --- | --- | --- |
+| Primary pccx action/accent | Use `#0b5fff` for primary action and focus surfaces. | Keep `#0b5fff` for the same structural accent surfaces. |
+| Editor foreground/background | Dark text on white or near-white editor surfaces. | Light text on near-black editor surfaces. |
+| Muted text | Lower-contrast gray that remains readable on light surfaces. | Higher-luminance gray that remains readable on dark surfaces. |
+| Selection/focus fill | Low-saturation blue fill that does not obscure syntax. | Deeper blue fill with enough contrast from the editor shell. |
+| Hover/secondary fill | Neutral gray fill distinct from the editor background. | Near-black or slate fill distinct from the editor background. |
+| Error/deleted | Red role for diagnostics and deletion. | Brighter red role for diagnostics and deletion. |
+| Warning/literals | Amber role for warnings and literal-like tokens. | Brighter amber role for warnings and literal-like tokens. |
+| Info/identifier | Blue role for information and identifier-like tokens. | Brighter blue role for information and identifier-like tokens. |
+| Added | Green role for additions. | Brighter green role for additions. |
+
+The shared accent `#0b5fff` is expected on paired structural surfaces such as
+buttons, focus borders, progress bars, modified gutters, activity badges, tab
+active borders, panel active borders, and prominent status bar items.  A dark
+theme may use a brighter related value for hover text, links, cursor, or syntax
+when contrast requires it.
+
+## Allowed Differences
+
+The dark theme may differ from the light theme for contrast and legibility:
+
+- background luminance and shell layering;
+- default, muted, inactive, and placeholder foreground values;
+- selection, hover, line-highlight, and find-match fills;
+- action hover colors;
+- terminal ANSI bright colors;
+- diagnostic foreground brightness;
+- link and cursor foreground brightness.
+
+Avoid introducing a new hue family or changing the meaning of a token bucket
+in only one theme.  For example, if keywords are purple in the light theme,
+the dark theme should use a contrast-adjusted purple rather than moving
+keywords to blue or green.
+
+## Review Checklist
+
+Before merging future theme changes:
+
+- Compare the two JSON files for key parity in `colors`.
+- Compare the two `tokenColors` arrays for matching bucket names, order, and
+  scope lists.
+- Confirm both themes still appear in `package.json` with the expected
+  `uiTheme` values and file paths.
+- Check that the primary pccx action/accent surfaces still use `#0b5fff`
+  unless a specific contrast exception is recorded.
+- Review diagnostics, gutter, and terminal colors as semantic pairs, not as
+  isolated palette values.
+- Capture or review both themes with the same fixture workspace, editor tab,
+  side bar, panel, status bar, selection state, and representative
+  SystemVerilog syntax.
+
+Do not use theme documentation or screenshots to imply marketplace
+availability, production readiness, stable API/ABI, LSP support, provider
+runtime calls, launcher calls, pccx-lab execution, or completed custom theme
+support.

editors/vscode-prototype/package.json

@@ -133,6 +133,11 @@
         "label": "pccx SystemVerilog Light",
         "uiTheme": "vs",
         "path": "./themes/pccx-systemverilog-light-color-theme.json"
+      },
+      {
+        "label": "pccx SystemVerilog Dark",
+        "uiTheme": "vs-dark",
+        "path": "./themes/pccx-systemverilog-dark-color-theme.json"
       }
     ],
     "configuration": {

editors/vscode-prototype/test/extension-manifest.test.mjs

@@ -123,6 +123,11 @@ async function testVisualAssetContributions() {
       uiTheme: "vs",
       path: "./themes/pccx-systemverilog-light-color-theme.json",
     },
+    {
+      label: "pccx SystemVerilog Dark",
+      uiTheme: "vs-dark",
+      path: "./themes/pccx-systemverilog-dark-color-theme.json",
+    },
   ]);
 
   const icon = await readBytes(resolve(EXTENSION_ROOT, manifest.icon));
@@ -148,6 +153,20 @@ async function testVisualAssetContributions() {
   )));
 }
 
+async function testThemeJsonTypes() {
+  const manifest = await readPackageJson();
+  const themes = manifest.contributes?.themes ?? [];
+
+  for (const contribution of themes) {
+    const theme = JSON.parse(await readText(resolve(EXTENSION_ROOT, contribution.path)));
+    if (contribution.uiTheme === "vs-dark") {
+      assert.equal(theme.type, "dark");
+    } else {
+      assert.equal(theme.type, "light");
+    }
+  }
+}
+
 async function testDocsKeepExperimentalScope() {
   const readme = await readText(resolve(EXTENSION_ROOT, "README.md"));
   const contract = await readText(resolve(ROOT, "docs/EDITOR_BRIDGE_CONTRACT.md"));
@@ -187,6 +206,7 @@ await testPackageManifestShape();
 await testNoMarketplacePublishingShape();
 await testCommandContributions();
 await testVisualAssetContributions();
+await testThemeJsonTypes();
 await testDocsKeepExperimentalScope();
 
 console.log("vscode extension manifest tests ok");