Implements the `export` and `import` app-level commands per
ADR-0015 §11 + ADR-0007 amendment 1.
- `export [<path>]` writes a zip of project.yaml + data/ to
<data-root>/YYYYMMDD-<projectname>-export-NN.zip by default,
preserving the project's directory name as the single
top-level folder inside the archive.
- `import <zip> [as <target>]` extracts an exported zip into
a new named project and switches to it. Target name is
derived from the zip's top-level folder by default; on
collision the destination auto-suffixes -02, -03, ... up
to -99 instead of refusing (deviates from §2's refuse-on-
collision rule for save/save as; recorded as an amendment
to ADR-0015 §11).
- Excludes playground.db and history.log from the zip.
- Path-traversal protection via zip::enclosed_name + post-
resolution check that the extraction path stays inside
the target directory.
Adds the zip = "5" dep with default-features = false +
features = ["deflate"] to keep the binary-size cost modest.
Test baseline: 370 passing, 0 failing, 0 skipped.
Designs track-2 lifecycle and persistence end-to-end: per-command
write-through to db+yaml+csv+history.log gated by the combined db
persistence logic with commit-db-last ordering; existence-only load
with explicit rebuild command; --resume CLI flag backed by
<data-root>/last_project; in-TUI list-with-browse picker; lock file
for single-instance enforcement; fatal-banner-then-quit failure
model (with --resume making restart cheap); fatal CSV row-load
errors with full diagnosis; YYYYMMDD-word-word-word temp naming
with display-name prettifier; collision-checked names for both
temp and user-supplied projects. Project name lives only on the
filesystem (not duplicated in YAML). ADR-0004 and ADR-0007 amended
in place. requirements.md and CLAUDE.md updated; OOS-6 (global
rolling history) tracked as deferred.