Universal data portability: CSV import/export, clearer backup labels, alarm fixes

[nufuturepro]

Universal data portability + supply tracking + alarm fixes

This PR bundles four improvements to Med, all verified working on-device:

1. CSV export/import (RFC 4180, zero dependencies)

• Export CSV joins the existing backup options in Advanced Settings. One row per schedule entry; hand-typed spreadsheets are valid imports — only title, creation_date, and creation_time are required.
• Quoting follows RFC 4180 (commas, quotes, and embedded newlines), so notes containing special characters round-trip correctly in Excel/Sheets.
• Import merges into existing data with the same semantics as JSON backups: existing entries match by ID and taken-dates are unioned, so re-importing a file never duplicates history.
• Imports also schedule alarms immediately, so restored meds remind right away instead of staying silent until the next reboot.
• A safety snapshot of current data is written before every import, so a bad file can never destroy existing records.

2. "Export Settings" → "Export Data"

The button has always exported a full backup (meds, history, and settings), but the label said "Settings" — users reasonably concluded it was not a data backup. All related labels and toasts now say "Data".

3. Supply (inventory) tracking with low-supply alerts

Per-medication stock tracking in the medicine editor:

• Track supply switch reveals three steppers: doses left, refill size (doses per refill, e.g. 30 tablets), and the alert threshold.
• Taking a dose decrements stock and un-taking restores it — consistently across all take paths (in-app, notification action, watch).
• Card badge shows "N left" and turns red at the threshold.
• A one-time low-supply notification fires per medication when stock reaches the threshold; it stays quiet until refilled, and stale alerts are cancelled automatically on refill, edit, or delete.
• Supply fields ride along in JSON backups and CSV (old files without them still import fine).

Audit hardening included from on-device testing:

• Per-item alert IDs, so several medications running low simultaneously do not overwrite each other's notifications.
• Threshold evaluation runs at app start, boot/reinstall, and import — supply that is already low alerts without waiting for a dose event.
• Race fix: toggling a dose from the UI now re-reads stored state first, so it cannot clobber a dose just logged from a notification or watch.

4. Lowest-supply home-screen widget

A resizable widget that always shows the medication with the lowest supply, including a progress bar toward the refill size and a red count at the threshold. It re-renders automatically on every data save — no polling, no battery cost.

5. Reminder fixes for early doses

Previously, logging a dose before the reminder time did not cancel that day's alarm (only the notification's Take button re-armed anything). Now:

• getNextOccurrence skips today's slot when already taken, so an early dose cancels the pending alarm.
• The in-app take/undo path re-arms alarms immediately — undoing an accidental "Taken" re-arms the same-day alarm, as expected.
• Notifications never fire for meds already logged today (fire-time race).

6. local.properties untracked

.gitignore already lists local.properties, but a committed copy was still tracked and silently overrode every contributor's SDK path. This untracks it (the file remains on disk locally).

Testing

• CSV round-trip (export → parse → export) is byte-stable; hand-written minimal CSVs import correctly.
• Supply tracking verified end-to-end on device: take decrements, un-take restores, threshold alert fires and de-duplicates, refill cancels the stale alert, widget updates on save.
• Reminder fixes verified on device: early take cancels the day's alarm; the alarm correctly advances to the next scheduled day.
• No behavior change for users who never touch the new features; existing JSON backups import unchanged.
• English-only strings, consistent with the existing codebase.