perf: fix streaming lag, memory leaks, stuck spinners, and proxy timeout (#483)

* perf: fix streaming lag, memory leaks, and proxy timeout

- PERF-001: Batch all streaming parts via requestAnimationFrame instead of
  per-token Zustand set() calls (~100/sec → 1 per frame)
- PERF-002: Fix direct state.sessionMemoryState mutation inside set() callback
- PERF-003: Debounce messageStore→sessionStore subscription via rAF + 500ms
  title computation delay
- PERF-004: Stabilize SSE callbacks with refs to prevent reconnection storms;
  add 5-min stuck session idle timeout
- PERF-005: Bound messageCache (500 max, LRU eviction), cap registry Maps,
  cleanup on session eviction
- PERF-006: Replace toast duration: Infinity with 30s + id-based dedup
- Fix proxy timeout: POST /session/:id/message 45s → 4min (matches CLI)
- Add vitest + jsdom test infrastructure (61 tests across 7 files)

Addresses: #476 (stuck spinner), #358 (34GB memory leak), #190 (browser lag)

* perf: virtualize tool output rendering (read, edit, write)

- PERF-007: Replace per-line <SyntaxHighlighter> with VirtualizedCodeBlock:
  - ONE Prism.highlight() call for entire file instead of N per-line calls
  - @tanstack/react-virtual renders only visible rows (~30 vs 2000+)
  - Applied to: ToolPart (read, DiffPreview, WriteInputPreview) and
    ToolOutputDialog (unified diff, read content)
- PERF-008: Memoize parseReadToolOutput/parseDiffToUnified via useMemo
  to prevent re-parsing on every re-render

A 2000-line file read now mounts ~30 DOM nodes instead of 2000
SyntaxHighlighter instances, eliminating the main-thread blocking
that caused UI freezes during file operations.

* fix: resolve lint errors (unused vars in tests and VirtualizedCodeBlock)

* chore: trim PR scope to core perf fixes

* fix: restore tool-card highlight stability

---------

Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>

bun.lock

@@ -151,6 +151,7 @@
         "@remixicon/react": "^4.7.0",
         "@streamdown/code": "^1.0.2",
         "@streamdown/mermaid": "^1.0.2",
+        "@tanstack/react-virtual": "^3.13.18",
         "@types/react-syntax-highlighter": "^15.5.13",
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
@@ -163,6 +164,7 @@
         "http-proxy-middleware": "^3.0.5",
         "motion": "^12.23.24",
         "next-themes": "^0.4.6",
+        "prismjs": "^1.30.0",
         "react": "^19.1.1",
         "react-dom": "^19.1.1",
         "react-syntax-highlighter": "^15.6.6",
@@ -180,6 +182,7 @@
         "@tailwindcss/postcss": "^4.0.0",
         "@tauri-apps/api": "^2.9.0",
         "@types/node": "^24.3.1",
+        "@types/prismjs": "^1.26.6",
         "@types/react": "^19.1.10",
         "@types/react-dom": "^19.1.7",
         "@vitejs/plugin-react": "^5.0.0",
@@ -1105,6 +1108,10 @@
 
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+    "@tanstack/react-virtual": ["@tanstack/react-virtual@3.13.18", "", { "dependencies": { "@tanstack/virtual-core": "3.13.18" }, "peerDependencies": { "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0", "react-dom": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0" } }, "sha512-dZkhyfahpvlaV0rIKnvQiVoWPyURppl6w4m9IwMDpuIjcJ1sD9YGWrt0wISvgU7ewACXx2Ct46WPgI6qAD4v6A=="],
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+
     "@tauri-apps/api": ["@tauri-apps/api@2.10.1", "", {}, "sha512-hKL/jWf293UDSUN09rR69hrToyIXBb8CjGaWC7gfinvnQrBVvnLr08FeFi38gxtugAVyVcTa5/FD/Xnkb1siBw=="],
 
     "@tauri-apps/cli": ["@tauri-apps/cli@2.10.0", "", { "optionalDependencies": { "@tauri-apps/cli-darwin-arm64": "2.10.0", "@tauri-apps/cli-darwin-x64": "2.10.0", "@tauri-apps/cli-linux-arm-gnueabihf": "2.10.0", "@tauri-apps/cli-linux-arm64-gnu": "2.10.0", "@tauri-apps/cli-linux-arm64-musl": "2.10.0", "@tauri-apps/cli-linux-riscv64-gnu": "2.10.0", "@tauri-apps/cli-linux-x64-gnu": "2.10.0", "@tauri-apps/cli-linux-x64-musl": "2.10.0", "@tauri-apps/cli-win32-arm64-msvc": "2.10.0", "@tauri-apps/cli-win32-ia32-msvc": "2.10.0", "@tauri-apps/cli-win32-x64-msvc": "2.10.0" }, "bin": { "tauri": "tauri.js" } }, "sha512-ZwT0T+7bw4+DPCSWzmviwq5XbXlM0cNoleDKOYPFYqcZqeKY31KlpoMW/MOON/tOFBPgi31a2v3w9gliqwL2+Q=="],
@@ -1251,6 +1258,8 @@
 
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+    "@types/prismjs": ["@types/prismjs@1.26.6", "", {}, "sha512-vqlvI7qlMvcCBbVe0AKAb4f97//Hy0EBTaiW8AalRnG/xAN5zOiWWyrNqNXeq8+KAuvRewjCVY1+IPxk4RdNYw=="],
+
     "@types/react": ["@types/react@19.2.13", "", { "dependencies": { "csstype": "^3.2.2" } }, "sha512-KkiJeU6VbYbUOp5ITMIc7kBfqlYkKA5KhEHVrGMmUUMt7NeaZg65ojdPk+FtNrBAOXNVM5QM72jnADjM+XVRAQ=="],
 
     "@types/react-dom": ["@types/react-dom@19.2.3", "", { "peerDependencies": { "@types/react": "^19.2.0" } }, "sha512-jp2L/eY6fn+KgVVQAOqYItbF0VY/YApe5Mz2F0aykSO8gx31bYCZyvSeYxCHKvzHG5eZjc+zyaS5BrBWya2+kQ=="],