[AI Generated][DOCS] 优化 README 并新增中文版

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -0,0 +1,36 @@
+name: Bug report
+description: Something works incorrectly or crashes
+labels: [bug]
+body:
+  - type: textarea
+    id: description
+    attributes:
+      label: Description
+      description: What happened, and what did you expect?
+    validations:
+      required: true
+  - type: input
+    id: version
+    attributes:
+      label: symcas version
+      description: Output of `cargo tree -i symcas` or the version in your Cargo.toml
+    validations:
+      required: true
+  - type: input
+    id: rust
+    attributes:
+      label: Rust version
+      description: Output of `rustc -V`
+  - type: dropdown
+    id: os
+    attributes:
+      label: OS
+      options: [Linux, macOS, Windows]
+  - type: textarea
+    id: repro
+    attributes:
+      label: Minimal reproduction
+      description: A self-contained code snippet that reproduces the issue
+      render: rust
+    validations:
+      required: true

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,18 @@
+name: Feature request
+description: Suggest new functionality or an improvement
+labels: [enhancement]
+body:
+  - type: textarea
+    id: problem
+    attributes:
+      label: Problem
+      description: What is missing or painful today?
+    validations:
+      required: true
+  - type: textarea
+    id: solution
+    attributes:
+      label: Proposed solution
+      description: What should symcas do instead?
+    validations:
+      required: true

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,12 @@
+## Summary
+
+<!-- What does this PR change and why? -->
+
+## Checklist
+
+- [ ] Summary explains motivation and the change itself
+- [ ] New/changed behavior is covered by tests (unit, doctest, or property tests)
+- [ ] `cargo fmt --all -- --check`, `cargo clippy --workspace --all-targets --locked -- -D warnings`, and `cargo test --workspace --locked` pass locally
+- [ ] No undocumented public API changes (doc comments updated)
+
+Closes #<issue number, if any>

.github/dependabot.yml

@@ -0,0 +1,14 @@
+version: 2
+updates:
+  - package-ecosystem: cargo
+    directory: /
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "chore(deps)"
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    commit-message:
+      prefix: "chore(deps)"

.github/workflows/release.yml

@@ -0,0 +1,27 @@
+# 推送 v* 标签时自动创建 GitHub Release，变更日志由 GitHub 自动生成。
+# 不含 crates.io 发布（需要 CARGO_REGISTRY_TOKEN secret，暂不引入）。
+name: Release
+
+on:
+  push:
+    tags: ["v*"]
+
+concurrency:
+  group: release-${{ github.ref }}
+  cancel-in-progress: false
+permissions:
+  contents: write
+
+jobs:
+  github-release:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+
+      - name: 创建 GitHub Release（自动生成变更日志）
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: gh release create "$GITHUB_REF_NAME" --generate-notes --verify-tag

Cargo.toml

@@ -16,7 +16,7 @@ edition = "2024"
 rust-version = "1.85"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/cislunarspace/cas"
-homepage = "https://github.com/cislunarspace/cas"
+homepage = "https://docs.rs/symcas"
 readme = "README.md"
 categories = ["mathematics", "science"]
 keywords = ["cas", "computer-algebra", "symbolic", "mathematics"]

README.md

@@ -4,6 +4,21 @@ Fast, deterministic computer algebra system in Rust.
 
 `symcas` provides a canonical expression arena with hash-consing, exact arithmetic over arbitrary precision rational numbers, ordered sparse multivariate polynomials, symbolic differentiation, series expansions, directed simplifications, roundtrip plain parsing, and LaTeX rendering.
 
+**English** | [简体中文](README.zh-CN.md)
+
+[![CI](https://github.com/cislunarspace/cas/actions/workflows/ci.yml/badge.svg)](https://github.com/cislunarspace/cas/actions/workflows/ci.yml)
+[![Crates.io](https://img.shields.io/crates/v/symcas)](https://crates.io/crates/symcas)
+[![Docs.rs](https://docs.rs/symcas/badge.svg)](https://docs.rs/symcas)
+[![License](https://img.shields.io/crates/l/symcas)](#license)
+
+## Contents
+
+- [Key Features](#key-features)
+- [Architecture](#architecture)
+- [Quickstart](#quickstart)
+- [Documentation](#documentation)
+- [License](#license)
+
 ## Key Features
 
 - **Canonical Construction & O(1) Equality**: Expressions are automatically normalized upon construction through flattening, term sorting, exact arithmetic folding, and like-term combination. Equivalent expressions within the same `Context` share an identical arena handle (`Expr::raw_id`).
@@ -32,11 +47,29 @@ Add `symcas` to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-symcas = "0.1.0"
+symcas = "0.1"
 ```
 
+Requires Rust 1.85+ (enforced via `rust-version` in Cargo.toml).
+
+### Basic Workflow
+
+Every symcas session follows the same standard procedure:
+
+1. **Create a `Context`**, the arena that owns every expression: `Context::new()`.
+2. **Create atoms**: `ctx.sym("x")` for symbols, `ctx.int(2)` for integers, `ctx.int(1) / ctx.int(2)` for exact rationals; declare several symbols at once with `sym!(&ctx, x, y)`.
+3. **Build or parse an expression**: combine atoms with `+`, `-`, `*`, `/`, `.pow(n)` and `ctx.call("sin", &[x.clone()])`, or read text with `symcas::parse(&ctx, "sin(x)^2")`. Construction canonicalizes immediately.
+4. **Transform it**: `ctx.expand(&e)`, `ctx.simplify(&e)`, `ctx.diff(&e, &x)`, `ctx.taylor(&e, &x, 0, 4)`, `ctx.subst(&e, &[("x", v)])`, `ctx.cancel(&e)`, `ctx.factor(&e)`.
+5. **Output the result**: `symcas::plain(&ctx, &e)` (roundtrip-safe machine format) or `symcas::latex(&ctx, &e)` (publication-ready).
+
+Each example below applies this procedure to one scenario.
+
 ### 1. Expressions & Canonical Form
 
+*Use this to tell whether two differently written formulas are the same math:*
+
+$$ (x + y)^{2} = x^{2} + 2xy + y^{2} \qquad x + x = 2x $$
+
 ```rust
 use symcas::prelude::*;
 
@@ -56,6 +89,10 @@ assert!(a == b);
 
 ### 2. Parsing & Roundtrip Guarantee
 
+*Use this to normalize loosely written input into one deterministic canonical form:*
+
+$$ x + x + \frac{1}{2}x \;\to\; \frac{5}{2}x $$
+
 ```rust
 use symcas::prelude::*;
 
@@ -70,6 +107,10 @@ assert!(back == e);
 
 ### 3. Expansion, Simplification & Substitution
 
+*Use this to verify hand-derived identities and declutter expressions:*
+
+$$ (x + y)^{2} = x^{2} + y^{2} + 2xy \qquad \sin^{2}x + \cos^{2}x = 1 $$
+
 ```rust
 use symcas::prelude::*;
 
@@ -93,6 +134,12 @@ assert_eq!(symcas::plain(&ctx, &sim), "1");
 
 ### 4. Differentiation & Taylor Expansion
 
+*Use this to compute derivatives too tedious by hand and local series approximations:*
+
+$$ \frac{\mathrm{d}}{\mathrm{d}x}\left(\sin(x)\,x^{2}\right) = 2x\sin(x) + x^{2}\cos(x) $$
+
+$$ e^{x} = 1 + x + \frac{x^{2}}{2} + \frac{x^{3}}{6} + \frac{x^{4}}{24} + \cdots $$
+
 ```rust
 use symcas::prelude::*;
 
@@ -112,6 +159,10 @@ assert_eq!(symcas::plain(&ctx, &s), "1 + x + 1/24*x^4 + 1/6*x^3 + 1/2*x^2");
 
 ### 5. Rational Reduction & Polynomial Operations
 
+*Use this to cancel common factors in rational expressions and expose roots by factoring:*
+
+$$ \frac{x^{2} - 1}{x - 1} = x + 1 \qquad x^{2} - 4 = (x - 2)(x + 2) $$
+
 ```rust
 use symcas::prelude::*;
 
@@ -129,6 +180,12 @@ let factored = ctx.factor(&poly);
 assert_eq!(symcas::plain(&ctx, &factored), "(-2 + x)*(2 + x)");
 ```
 
+## Documentation
+
+- [DESIGN.md](DESIGN.md): design document (Chinese), covering goals, decisions D1 to D6, and acceptance criteria
+- [MATLAB-PARITY.md](MATLAB-PARITY.md): feature parity status against MATLAB Symbolic Math Toolbox
+- API reference on [docs.rs](https://docs.rs/symcas)
+
 ## License
 
 Licensed under either of: