#70 ci: add default branch checks and codspeed benchmark

What changed

• Add an always-run Core CI workflow for PRs targeting personal/local-clients.
• Add a CodSpeed workflow and a small Rust normalization benchmark for initial advisory performance reporting.
• Include personal/local-clients in existing CI workflow branch filters and replace hardcoded main coverage badge conditions with the repository default branch.
• Make pricing command tests use fixture pricing caches instead of leaking to live network/cache state.

Why

This prepares the self-maintained fork default branch for ruleset protection and CodSpeed without blocking normal solo-maintainer direct pushes. The core required check can be enabled after this workflow lands on the default branch.

Validation

• cargo fmt --all -- --check
• cargo clippy --locked --workspace --all-features -- -D warnings
• cargo test --locked --workspace --all-features
• cargo bench --locked -p tokscale-core --bench normalization -- --test

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Summary by cubic

Add Core CI for PRs targeting personal/local-clients, add CodSpeed benchmarks (simulation) for normalization and JSON/JSONL parsing, and restrict coverage to default-branch, non-PR runs with artifacts only. Actions are pinned to SHAs, pricing CLI tests are stabilized, and core dev-dependencies are centralized.

• New Features

  • Core CI for PRs to personal/local-clients.
  • CodSpeed workflow with codspeed-criterion-compat benches for normalization and JSON/JSONL parsing; bench profile optimized for CI; CodSpeed badge in README.
  • CI workflows include personal/local-clients in branch filters; Actions pinned to SHAs; core dev-dependencies centralized.

• Bug Fixes

  • Pricing command tests use local fixture caches and a temp HOME to avoid flakiness.
  • Fixed cargo cache/install conflict in the CodSpeed job.
  • Coverage: only on non-PR runs on the repository default branch with read-only permissions; removed badge generation/extraction and commits; artifacts only.

Summary by CodeRabbit

• Chores
  • 新增 CodSpeed 性能测试工作流，并完善 Core CI 与代码覆盖率流程
  • 扩展多套 CI 工作流的触发分支范围，且将关键构建步骤固定到可复现的版本
  • 调整基准构建与运行配置（如 bench 构建选项与相关依赖）
• Tests
  • 新增核心归一化/解析相关基准测试
  • 改进定价相关 CLI 测试：统一使用隔离的临时 HOME 与定价夹具环境
• Documentation
  • README 增加 CodSpeed 指标徽标展示