v0.1.2

[0.1.2] — 2026-06-18

A feature + hardening release. The headline is Thunderbird subfolder (.sbd) support — a new
CLI discover command that reconstructs a nested folder tree from a Thunderbird mail directory and
converts it to nested PST folders. This is currently CLI-only; the desktop app does not yet expose
it. The rest of the release is correctness, security, and robustness work that benefits everyone,
desktop users included.

Added

• Thunderbird .sbd nested-folder support (CLI). A new discover command walks a mail-files
  directory (e.g. a Thunderbird "Local Folders" or account directory), reconstructs the nested tree
  from Thunderbird's <name> + sibling <name>.sbd/ layout, and emits a JSON source list with an
  explicit nested targetFolderPath per source. Feeding that into convert produces a PST with the
  folder hierarchy preserved. A plain directory of .mbox files still works as before.
• Nested folder paths in config. convert sources accept a targetFolderPath array (e.g.
  ["Inbox","Archive","2026"]) to place mail into nested PST folders; the engine creates the full
  path on demand. The existing targetFolder string remains single-segment shorthand.
• schemaVersion on every CLI JSON event so consumers can detect contract changes; the desktop
  app checks it permissively.

Changed

• CLI project/binary renamed mbox2pst → mail2pst (sidecar mail2pst-cli). The product name
  (ContinuMail Converter) is unchanged; this only affects anyone invoking the CLI by its old name.
• PST size-splitting is now predictive — a part splits before a message would cross the cap,
  rather than only at a periodic checkpoint (which could overshoot a small custom cap).
• Desktop app now uses a restrictive, local-only Content-Security-Policy (previously unset).

Fixed

• NDR/bounce phantom attachment (KB-001). Bounce notifications no longer surface a phantom
  embedded-message attachment in Outlook, regardless of how deeply the multipart/report is nested.
• Stricter, cross-platform output-name validation — reserved names, trailing space/period, and
  platform-invalid characters are rejected up front (#17).
• Envelope-postmark validation — the From boundary validates the day-of-week and month, so a
  body line that merely looks like a postmark can't cause a mis-split (#2).
• More accurate (component-aware) split-cap size estimate, so very large messages split correctly (#4).
• A permission-denied source is skipped and reported instead of crashing the run; an empty sender
  address no longer fails a write; a config/output-dir setup failure emits a fatal JSON error instead
  of a bare crash; the mbox parse enumerator is disposed promptly on early exit.

Known limitations

• Thunderbird read/unread & starred state is not preserved. Thunderbird stores per-message flag
  state in its .msf index, not the mbox, so an mbox-based conversion cannot recover it (messages
  generally import as read & unflagged). Read/unread is preserved for archives whose mbox carries
  real X-Mozilla-Status flags. (KB-002.)

Internal

• New format-agnostic round-trip integration test harness (parse → write → PST read-back →
  compare), CI on every push/PR, and Dependabot. The PST writer and MIME mapping were
  decomposed for maintainability. No behaviour change.