refactor: unify Crabfleet coordinator architecture

[steipete]

Summary

• split the Worker and browser app into focused route, service, repository, policy, and presentation modules
• make Crabbox /v1/workspaces the only external workspace lifecycle protocol and /api/terminal/ws terminal protocol v2 the only browser, CLI, and gateway terminal transport
• remove legacy providers, direct PTY client transport, compatibility aliases, fallback framing, permissive runtime selection, and obsolete host routes
• replace browser-native session alerts, confirms, and prompts with accessible HTML dialogs, inline errors, stable focus handling, and explicit progress state
• preserve and integrate scoped OpenClaw embed tickets, configurable interactive runtimes, embedded Ghostty WASM assets, and PTY readiness
• centralize session creation, reconciliation, stop/finalization, credential-policy cleanup, GitHub Actions, OpenClaw supervision, and terminal persistence ownership

Architecture

• reduce src/index.ts from the monolithic implementation to Worker entry points, routing, and dependency composition
• move D1 access into repositories and transactional lifecycle owners
• share one authorization, presentation, terminal-route, URL-security, deployment, and lifecycle policy per concern
• split the frontend into state, routing, dialog, drawer, board, session workspace, and shell components
• share Go control-plane models, HTTP behavior, rendering, and terminal framing between the CLI and SSH gateway

Behavior changes

• terminal protocol v2 requires exact 20-byte Subscribe payloads and rejects old or trailing framing
• zero terminal dimensions use the server's 120x34 defaults
• unsupported runtime profiles, removed providers, old routes, and old environment aliases fail explicitly
• shared terminal links remain read-only; scoped embed tickets may authorize session-specific terminal input
• terminal and desktop availability are derived from current runtime capability and route readiness

Validation

• pnpm test (604 tests)
• pnpm check
• pnpm build
• go test ./...
• go vet ./...
• git diff --check
• local checkpoint autoreview clean, confidence 0.87
• full branch autoreview clean, confidence 0.72

[clawsweeper]

ClawSweeper status: review started.

I am starting a fresh review of this pull request: refactor: unify Crabfleet coordinator architecture This is item 1/1 in the current shard. Shard 0/1.

This placeholder means the worker is alive and reading the current context. I will edit this same comment with the actual review when the claws are done clicking.

Crustacean status: shell secured, claws on keyboard, evidence pebbles being sorted.