Story 18: Token-by-token streaming responses

- Backend: Added OllamaProvider::chat_stream() with newline-delimited JSON parsing
- Backend: Emit chat:token events for each token received from Ollama
- Backend: Added futures dependency and stream feature for reqwest
- Frontend: Added streamingContent state and chat:token event listener
- Frontend: Real-time token display with auto-scroll
- Frontend: Markdown and syntax highlighting support for streaming content
- Fixed all TypeScript errors (tsc --noEmit)
- Fixed all Biome warnings and errors
- Fixed all Clippy warnings
- Added comprehensive code quality documentation
- Added tsc --noEmit to verification checklist

Tested and verified:
- Tokens stream in real-time
- Auto-scroll works during streaming
- Tool calls interrupt streaming correctly
- Multi-turn conversations work
- Smooth performance with no lag

.living_spec/README.md

@@ -100,3 +100,63 @@ If a user hands you this document and says "Apply this process to my project":
 4.  **Draft Context:** Write `specs/00_CONTEXT.md` based on the user's answer.
 5.  **Draft Stack:** Write `specs/tech/STACK.md` based on best practices for that language.
 6.  **Wait:** Ask the user for "Story #1".
+
+---
+
+## 6. Code Quality Tools
+
+**MANDATORY:** Before completing Step 4 (Verification) of any story, you MUST run all applicable linters and fix ALL errors and warnings. Zero tolerance for warnings or errors.
+
+### TypeScript/JavaScript: Biome
+
+*   **Tool:** [Biome](https://biomejs.dev/) - Fast formatter and linter
+*   **Check Command:** `npx @biomejs/biome check src/`
+*   **Fix Command:** `npx @biomejs/biome check --write src/`
+*   **Unsafe Fixes:** `npx @biomejs/biome check --write --unsafe src/`
+*   **Configuration:** `biome.json` in project root
+*   **When to Run:**
+    *   After every code change to TypeScript/React files
+    *   Before committing any frontend changes
+    *   During Step 4 (Verification) - must show 0 errors, 0 warnings
+
+**Biome Rules to Follow:**
+*   No `any` types (use proper TypeScript types or `unknown`)
+*   No array index as `key` in React (use stable IDs)
+*   No assignments in expressions (extract to separate statements)
+*   All buttons must have explicit `type` prop (`button`, `submit`, or `reset`)
+*   Mouse events must be accompanied by keyboard events for accessibility
+*   Use template literals instead of string concatenation
+*   Import types with `import type { }` syntax
+*   Organize imports automatically
+
+### Rust: Clippy
+
+*   **Tool:** [Clippy](https://github.com/rust-lang/rust-clippy) - Rust linter
+*   **Check Command:** `cargo clippy --all-targets --all-features`
+*   **Fix Command:** `cargo clippy --fix --allow-dirty --allow-staged`
+*   **When to Run:**
+    *   After every code change to Rust files
+    *   Before committing any backend changes
+    *   During Step 4 (Verification) - must show 0 errors, 0 warnings
+
+**Clippy Rules to Follow:**
+*   No unused variables (prefix with `_` if intentionally unused)
+*   No dead code (remove or mark with `#[allow(dead_code)]` if used conditionally)
+*   Use `?` operator instead of explicit error handling where possible
+*   Prefer `if let` over `match` for single-pattern matches
+*   Use meaningful variable names
+*   Follow Rust idioms and best practices
+
+### Build Verification Checklist
+
+Before asking for user acceptance in Step 4:
+
+- [ ] Run `cargo clippy` (Rust) - 0 errors, 0 warnings
+- [ ] Run `cargo check` (Rust) - successful compilation
+- [ ] Run `cargo test` (Rust) - all tests pass
+- [ ] Run `npx @biomejs/biome check src/` (TypeScript) - 0 errors, 0 warnings
+- [ ] Run `npm run build` (TypeScript) - successful build
+- [ ] Manually test the feature works as expected
+- [ ] All acceptance criteria verified
+
+**Failure to meet these criteria means the story is NOT ready for acceptance.**