added ntfy support for scheduled runs

CHANGELOG.md

@@ -6,6 +6,7 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [Unreleased]
 
 ### Fixed
+- **An em dash in a notification title silently dropped the notification.** HTTP header values are latin-1 at best and `requests` raises on anything outside it, so the first real send failed with `'latin-1' codec can't encode character '\u2014'`. Header values are now flattened to ASCII (smart punctuation mapped to its plain equivalent); the body is unaffected, being sent as UTF-8 bytes. Found by sending a test push rather than by reading the code.
 - **The terms-of-service gate exited 0 without a terminal.** `click.prompt` raises `Abort` on a closed stdin, which the handler treated as a user Ctrl-C and exited 0 — so a scheduled run on a machine that had never acknowledged the notice would report success having archived nothing. Non-interactive invocations now exit 1 with an explanation of how to clear the gate once by hand. Found by running the new systemd unit rather than by reading the code.
 - **A single U+0085 in a transcript silently dropped a whole record.** Both local providers split session files with `str.splitlines()`, which breaks not just on `\n` but on U+0085 (NEL), U+2028 and U+2029 — all of which are legal *inside* a JSON string and are written literally by Codex (Rust does not escape non-ASCII). One NEL in captured command output shredded one record into unparseable fragments; the parser logged "skipped 3 unparseable line(s)" and lost the record. Found while exporting a real rollout. Both providers now split on `\n` only, and both have regression tests that write their fixtures with `ensure_ascii=False` — with `json.dumps`' default the hazardous characters are escaped and the bug cannot reproduce.
 - **Deleted uploads are no longer reported as permission errors.** ChatGPT's `/backend-api/files/{id}/download` answers a *missing* asset with `403 {"detail":"Forbidden"}`, which reads like an auth failure and isn't one. Measured live 2026-08-17 across 18 such assets: every one returned `404 {"detail":"File not found"}` on `/files/{id}`, while assets that downloaded fine returned 200 on both in the same session, and `ChatGPT-Account-Id` made no difference. A 403 is now confirmed against the metadata endpoint before being reported (one extra request on the failure path only, none on success) and a confirmed-missing asset is logged as gone and counted as `expired-or-missing`. A 403 on an asset that *does* still exist is left alone as `forbidden` — that one would be a real problem.
@@ -14,6 +15,9 @@ Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - **`tests/test_config.py::TestSessionLimiterConfig::test_defaults` depended on the developer's `.env`.** `load_config()` calls `load_dotenv(override=False)`, which re-populated the variable the test had just deleted — so it passed only on a machine with no `.env`. The test now stubs dotenv discovery.
 
 ### Added
+- **ntfy push notifications for unattended runs (`NTFY_TOPIC`).** A scheduled archive reports only to places you have to go and look at — the log file, the systemd journal, Task Scheduler's exit code — so a run that quietly failed every morning would stay quiet. `sync` now pushes its result: success carries per-provider counts at low/default priority, failure carries the reason at high priority with an alert tag, so the two are distinguishable at a glance on a phone. `ai-chat-exporter notify` shows the settings and `--test` sends a test push. `NTFY_NOTIFY=failure` limits it to failures, `off` disables, `--notify`/`--no-notify` override per run. Never fatal: an unreachable ntfy logs a warning and the run still reports its real exit code.
+
+  The payload is **counts and a machine name only, never conversation titles** — a topic on public ntfy.sh is readable by anyone who knows its name, and a title is the first line of what you asked. The machine name is included because several machines archive into one topic, where "2 exported" means nothing on its own. `NTFY_SERVER` points at a self-hosted instance and `NTFY_TOKEN` authenticates against an access-controlled topic.
 - **`ai-chat-exporter` / `ai-chat-exporter.cmd` launchers — no virtualenv ceremony.** `cd` into the repo and run; the wrapper creates `.venv`, installs dependencies on first run, and reinstalls when `pyproject.toml` changes. A fresh clone goes from nothing to a working command in one step (measured: ~10s), on Linux/macOS and Windows alike, which matters for a tool meant to run on several machines. `cmd.exe` searches the current directory before `PATH`, so Windows needs no `.\` prefix. The working directory is deliberately not changed — `.env`, `cache/` and `exports/` still resolve against it, which is what lets one checkout archive different machines into different places — but the wrapper now warns when you run it from elsewhere, because a different `cache/manifest.json` silently starts a *second* archive rather than failing.
 - **`sync` command — `export` then `joplin` in one invocation, with a real exit code.** Intended for schedulers (and the "trivial add-on" FUTURE.md §7 anticipated): it exits non-zero if any conversation failed to export or any note failed to sync, so a scheduled run that achieved nothing is distinguishable from one that had nothing to do. `--skip-joplin` exports only; `--joplin-optional` downgrades an unreachable Joplin to a warning, since the export has already captured the local transcripts and the notes rebuild from the cache on the next run that finds Joplin up.
 - **Daily scheduling for both platforms.** `scheduling/install-systemd-timer.sh` (systemd user timer, `Persistent=true` so a machine that was off catches up at boot) and `scheduling/Register-AiChatSyncTask.ps1` (per-user Task Scheduler entry, `-StartWhenAvailable`). `--provider` is repeatable in both, because the right set differs per machine: the local providers need no credentials and always work unattended, while a web provider whose session token has expired would fail the job every single day and train you to ignore it.