fix(update): automate semantic reconciliation

[epodivilov]

What

• classify diverged feature tracking refs by patch-equivalent commits in both directions
• preserve stale local rebases, automatically reconcile semantic remote work, and keep reset explicit
• report only actionable reconciliation rows by default, add verbose diagnostics, actionable unresolved summaries, and phase-aware progress

Why

wt update must handle rebased-but-unpushed PR branches without prompt storms, unnecessary resets, or opaque unresolved failures.

Verification

• bun test (714 passing; executed via pnpm dlx bun because Bun is not installed globally)
• bun run typecheck
• bun run lint

Not verified: manual update against a real repository with rebased-but-unpushed PR branches.