refactor(digitalocean): extract 3 helpers from 260-line tryDoOAuth

[la14-1]

Why: tryDoOAuth() was 260 lines with 4 distinct responsibilities (connectivity check, HTTP callback server, terminal I/O wait loop, token exchange) — extracting reduces cognitive load and makes each piece independently testable.

Changes

Split tryDoOAuth() in packages/cli/src/digitalocean/digitalocean.ts into 3 focused helpers:

• startOAuthCallbackServer(csrfState) — Starts Bun.serve on localhost, scanning ports 5190-5199. Returns the server, actual port, and a shared OAuthCallbackState object that the callback handler mutates.
• waitForOAuthCallback(cbState, server) — Handles the initial 120s polling timeout, non-interactive timeout, and extended interactive wait with raw-mode Escape-key detection. Returns a discriminated outcome: "code" | "denied" | "manual" | "timeout".
• exchangeOAuthCode(code, redirectUri) — POSTs to the DigitalOcean token endpoint and persists the access/refresh tokens.

tryDoOAuth() is now a ~45-line orchestrator that checks connectivity, delegates to each helper, and maps outcomes to return values.

Verification

• bunx @biomejs/biome check src/ — 0 errors (193 files)
• bun test — 2106 pass, 2 fail (same 2 pre-existing failures on main)
• DigitalOcean-specific tests (digitalocean*.test.ts) — 9 pass, 0 fail

-- spawn-refactor/complexity-hunter

[la14-1]

Rebased onto main to resolve merge conflicts (package.json version bump).

-- refactor/pr-maintainer

[la14-1]

Fixed CI: removed duplicate "version" key in packages/cli/package.json that was introduced during the rebase. bun install was failing with Duplicate key "version" in object literal. CI should pass now.

-- refactor/pr-maintainer

[la14-1]

This PR has been open for 3+ days with all CI checks passing (ShellCheck, Mock Tests, Biome Lint, Unit Tests, macOS Compatibility — all SUCCESS). It is mergeable with no conflicts.

Requesting human review when convenient.

-- refactor/pr-maintainer

[la14-1]

Rebased onto main (dropped the now-redundant duplicate-version-key fix commit). Branch is clean with 1 commit. Awaiting human review.

-- refactor/pr-maintainer

[la14-1]

This PR is ready for review. All CI checks pass and there are no merge conflicts.

-- refactor/pr-maintainer

[la14-1]

Rebased onto main (was 4 commits behind). Clean rebase, no conflicts.

-- refactor/pr-maintainer

[la14-1]

Verified in worktree: tests pass (2236/2238, same 2 pre-existing failures as main), lint clean (biome 0 errors). PR is mergeable and ready for review.

-- refactor/pr-maintainer