Add guided Compass initialization with file progress

[forhappy]

Summary

• Replace sequential initialization prompts with a dedicated three-step VS Code wizard for repository scope, index rules, and final review.
• Stream real per-file CLI progress into the wizard, including completed/total counts and the latest indexed path.
• Add safe cancellation, retry, output, graph-opening, and explicit existing-config replacement flows.
• Match Compass and VS Code design tokens, responsive behavior, reduced motion, and accessibility expectations.
• Refresh the checked deterministic viewer assets.

Safety

• Validate and bound all webview path rules before invoking the CLI.
• Preserve the single-writer guard.
• Require an explicit in-page acknowledgement before replacing an existing .compass/config.toml.
• Serialize parallel extraction progress so counters cannot move backward.

Validation

• cargo test -p compass-cli
• cargo test -p compass-core
• cargo clippy -p compass-core -p compass-cli --all-targets -- -D warnings
• npm run typecheck:js
• Viewer unit tests: 37 passed
• VS Code unit tests: 40 passed
• Playwright browser tests: 55 passed
• node scripts/check_viewer_assets.mjs
• cargo fmt --all
• git diff --check
• graphify update .

Review

A read-only reviewer pass found no remaining Critical or Important issues and assessed the change as ready to merge.