feat: generate v1 API client from OpenAPI

[EastSun5566]

What

• Generate @hackmd/api/raw from the v1 OpenAPI spec while keeping the existing API class compatible.
• Cover all 59 v1 operations and fix retry isolation.
• Derive public response types from OpenAPI, correcting handwritten mistakes such as note createdAt and lastChangedAt being typed as string instead of number.

Documentation

• TypeDoc builds a static API reference from the public API and @hackmd/api/raw types (pnpm docs:build).
• The Pages workflow deploys it on pushes to master. Before the first deployment, set Settings → Pages → Build and deployment → Source: GitHub Actions in this repository.

Related work

• CLI PR #119 adds generic v1 commands using @hackmd/api/raw.

Checks

• Generated-code check, typecheck, 111 unit tests, build, and TypeDoc pass.
• All 12 existing live E2E tests pass against production with HACKMD_E2E_MUTATIONS=1.

Before marking ready

• Wait for the hackmd OpenAPI update, then refresh the vendored spec and regenerate.

Fixes #61 #60

[EastSun5566]

types gen docs: