Fix Google Calendar Obsidian link escaping

[martin-forge]

Summary

• Escape the Obsidian URI query separator in Google Calendar sync descriptions as &file=.
• Keep the link plain text and update the focused service test plus release note.

Why

Google Calendar descriptions are HTML-capable. Leaving the raw &file= separator in the description can be handled as an HTML entity boundary by Calendar clients, which breaks the Obsidian open link path parameter.

Testing

• npm test -- --runTestsByPath tests/services/TaskCalendarSyncService.test.ts
• npm run build:test
• npm run lint
• Upstream CI passed: docs, test (20), and build-test.

[martin-forge]

Closing this — I tested the premise and it does not hold.

I created two Google Calendar events, one storing a raw & in the description and one storing &, and read both back through the API. Google stores the field byte-for-byte and normalises nothing. Rendering then differs by client:

• Apple Calendar on macOS decodes & to & and auto-linkifies the URL, so both events displayed an identical working link. The raw & was never broken there.
• TaskNotes' own calendar event modal renders the description as plain text and does not decode entities, so & appears literally and the Obsidian URI is broken.

So this change fixes nothing I could reproduce and breaks the link in TaskNotes itself. Apologies for the noise.