feat(calendar-sync): add Python helper for Google Calendar API sync

Google's .ics export drops per-occurrence response statuses on recurring events. When OOO auto-declines a meeting, the master event keeps PARTSTAT=ACCEPTED and declined instances inherit it. The .ics path can't filter the declines out. The API path expands recurrences server-side via singleEvents=True, and each occurrence carries its own attendees[].self.responseStatus.

scripts/calendar_sync_api.py fetches events and renders them as org entries. OAuth is one-time per account. The refresh token lives at ~/.config/calendar-sync/token-<account>.json under 0600. Output matches the existing .ics shape: heading sanitization, LOCATION/ORGANIZER/STATUS/URL property drawer, HTML-stripped descriptions, org timestamps with weekday abbreviations.

I wrote 30 stdlib-unittest tests against fixture JSON, covering rendering, filtering, timestamp formatting, and HTML cleanup. I left auth and HTTP uncovered — they're thin wrappers around the Google client libraries, best checked by running the script once after OAuth setup.

docs/calendar-sync-api-setup.org walks through the Google Cloud OAuth client setup and the per-account auth bootstrap. .gitignore picks up Python bytecode now that the project has a Python helper.

The Elisp dispatch (:fetcher 'api routing in calendar-sync.el) lands in a follow-up commit.

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/fixtures/calendar-sync-api/all-day-multi.json b/tests/fixtures/calendar-sync-api/all-day-multi.json
new file mode 100644
index 00000000..96d9e0ed
--- /dev/null
+++ b/tests/fixtures/calendar-sync-api/all-day-multi.json
@@ -0,0 +1,8 @@
+{
+  "id": "fjamsabuds9porc82vh8r7tsl4",
+  "summary": "SOFWeek — Tampa",
+  "location": "Tampa, FL",
+  "start": {"date": "2026-05-17"},
+  "end":   {"date": "2026-05-22"},
+  "status": "confirmed"
+}