fix(theme): --ot-* 变量名 camelCase/kebab-case 不匹配导致浅色分支静默失效

CSS 自定义属性名大小写敏感，而 semanticVars() 的键是 camelCase、样式表读的是
kebab-case：chrome.ts 直接写 `--ot-${key}` 时，9 个多词变量（--ot-text-muted、
--ot-text-secondary、--ot-surface-raised、--ot-border-strong、--ot-success-fg、
--ot-danger-fg、--ot-warning-fg、--ot-info-fg、--ot-scrollbar-active、
--ot-focus-ring）从未真正生效，元素一律回落到 global.css :root 的深色兜底值——
浅色主题正是靠这些变量修可读性的，等于白改（--ot-text-muted 48 处引用仍是
#8a8a8a，白底 3.25:1；--ot-danger-fg 仍是 #f85149，3.15:1）。

- 键 `muted` 改名 `textMuted`（CSS 读的是 --ot-text-muted）
- 新增 semantic.ts 的 cssVarName()/semanticCssVars()，chrome.ts 只调用它们，
  命名逻辑单一来源
- 新增 tests/ot-var-names.mjs：把「CSS 引用名 = JS 写入名 = :root 声明名」
  三集合锁在一起（值测试看不出这类问题），已用「去掉转换」验证会失败
- AGENTS/STATE 同步该铁律；测试数 22/25 的陈旧计数修正为实际的 29

package.json

@@ -13,7 +13,7 @@
     "preview": "electron-vite preview",
     "typecheck": "tsc --noEmit -p tsconfig.node.json && tsc --noEmit -p tsconfig.web.json",
     "pretest": "npm run typecheck",
-    "test": "node tests/build-bundles.cjs && node tests/ssh-loopback.mjs && node tests/commands-store.mjs && node tests/connections-store.mjs && node tests/settings-store.mjs && node tests/local-path-grants.mjs && node tests/lock-store.mjs && node tests/lock-controller.mjs && node tests/lock-shortcuts.mjs && node tests/reserved-accelerators.mjs && node tests/.terminal-title.cjs && node tests/ipc-guard.mjs && node tests/updater-fallback.mjs && node tests/log-sanitizer.mjs && node tests/app-log.mjs && node tests/sftp-timeout.mjs && node tests/.hl-split-smoke.cjs && node tests/.hl-rules.cjs && node tests/zmodem-e2e.mjs && node tests/ssh-session-e2e.mjs && node tests/sysinfo-e2e.mjs && node tests/terminal-cwd.mjs && node tests/terminal-links.mjs && node tests/broadcast-store.mjs && node tests/write-batcher.mjs && node tests/refit-throttle.mjs && node tests/semantic-theme.mjs && node tests/theme-contrast.mjs && node tests/css-theme-vars.mjs",
+    "test": "node tests/build-bundles.cjs && node tests/ssh-loopback.mjs && node tests/commands-store.mjs && node tests/connections-store.mjs && node tests/settings-store.mjs && node tests/local-path-grants.mjs && node tests/lock-store.mjs && node tests/lock-controller.mjs && node tests/lock-shortcuts.mjs && node tests/reserved-accelerators.mjs && node tests/.terminal-title.cjs && node tests/ipc-guard.mjs && node tests/updater-fallback.mjs && node tests/log-sanitizer.mjs && node tests/app-log.mjs && node tests/sftp-timeout.mjs && node tests/.hl-split-smoke.cjs && node tests/.hl-rules.cjs && node tests/zmodem-e2e.mjs && node tests/ssh-session-e2e.mjs && node tests/sysinfo-e2e.mjs && node tests/terminal-cwd.mjs && node tests/terminal-links.mjs && node tests/broadcast-store.mjs && node tests/write-batcher.mjs && node tests/refit-throttle.mjs && node tests/semantic-theme.mjs && node tests/theme-contrast.mjs && node tests/css-theme-vars.mjs && node tests/ot-var-names.mjs",
     "predist": "node scripts/verify-deps.cjs && npm test && npm install --package-lock-only",
     "dist": "electron-vite build && electron-builder --win nsis",
     "dist:dir": "electron-vite build && electron-builder --win --dir"