Prepare v0.3.3 release

[rohoswagger]

Bumps to 0.3.3 and records the release in the version history. Cargo.lock is regenerated in the same commit because the release workflow runs cargo publish --locked.

0.3.2 is already tagged and published to crates.io, so this is the next version — tags are never reused.

What's in 0.3.3

All four PRs address the same underlying theme: stack metadata is a cache of git, and treating it as the source of truth produces confident wrong answers.

• fix: derive needs_restack from git, not stale parent_head #141 — ez status derived needs_restack by comparing the parent tip to the cached parent_head, so a branch rebased outside ez reported that it needed a restack when it was already sitting on its parent. Now asks git, via a shared restack::branch_needs_restack that ez checkout also uses — the two commands previously disagreed about the same branch.
• fix: run the post-merge restack through the shared engine #142 — ez merge's post-merge restack was its own loop predating the shared engine from 0.2.29. A stack entry whose branch was gone aborted the whole command after the PR had merged, so a successful merge exited 1. It now runs through restack_branches_with_options, gaining missing-branch skips, the effective_old_base fallback, per-branch isolation, and the worktree guard.
• fix: never strand a merged branch when the post-merge restack fails #143 — the merged branch was cleaned up after that restack, behind a ?. A restack failure therefore skipped cleanup once the stack entry was already deleted, leaving a branch and worktree no command could see. Cleanup now runs first, and ez sync gained a safety net that collects orphans under this repo's .worktrees/.
• fix: identify an orphan's PR by head SHA, not by branch name #144 — that safety net couldn't actually fire: its squash-merge check relied on an empty diff against trunk, which only holds for a restacked branch. Merge evidence is now identity-based — a merged PR counts only when its headRefOid matches the local tip, so a recycled branch name or a fork contributor's same-named PR can't authorize a deletion.

Backfill

The version history table stopped at 0.2.29; 0.3.0, 0.3.1, and 0.3.2 were never written down. Added from their tag ranges.

Full suite and clippy green.