fix: show changes created by OpenSpec 1.0+, and what each one is waiting for (0.2.0)

[ToruGuy]

The bug

A change was only recognised if it contained proposal.md. Current OpenSpec writes .openspec.yaml when the change is created, and the proposal only once an agent drafts it — so every freshly created change was missing from the board until someone wrote a proposal, which is the exact moment you most want to see it.

Verified against OpenSpec 1.6:

$ openspec new change test-feature
$ find openspec -type f
openspec/config.yaml
openspec/changes/test-feature/.openspec.yaml     # ← the only file

Either marker now identifies a change, so the pre-1.0 layout keeps working too.

What the board says now

Each change reports its artifact chain — proposal, design, specs, tasks — as complete, ready (dependencies met, nothing blocking it) or blocked, with the artifacts it is waiting for:

second-change    proposal:ready    → design:blocked  → specs:blocked → tasks:blocked
test-feature     proposal:complete → design:ready    → specs:ready   → tasks:blocked

Vocabulary and dependency graph match openspec status --change <name> field for field (diffed against the real CLI), but everything is derived from the files on disk — so no OpenSpec install is needed in the repos being watched, and the dashboard stays read-only. Cards mark the next actionable artifact instead of only showing what already exists.

Housekeeping the release needed

• CI on push and PR (frontend build, cargo test, cargo clippy -D warnings). Nothing verified commits before this, which is how 14 clippy warnings and a broken parser assumption accumulated unnoticed. Warnings fixed.
• release.yml publishes archives from a v* tag for four targets (adds macOS Intel). The four dispatch-only workflows it replaces built the same binaries but only uploaded them as build artifacts, so cutting a release meant downloading and re-uploading by hand. A workflow_dispatch entry point is kept.
• Removed readyForReview from the Change type — declared in the frontend contract, never sent by the backend, never read by any component.
• Removed a file literally named --config: a shell mishap committed a copy of the example config under that name.
• CHANGELOG.md added; VERSION and Cargo.toml stamped 0.2.0.

Verification

• cargo test — 8 passed (5 new: artifact chain at each stage, schema reading, marker-only change visibility)
• cargo clippy — 0 warnings
• Frontend vitest — 4 passed; npm run build clean
• End-to-end against a repo created by OpenSpec 1.6, output diffed against openspec status --change <name> --json