Another round of bug fix while waiting for 1.0

What's Changed

• Pin KOReader Core checkout to stable v2025.10 by @dani84bs in #43
• fix: some initial sync issues by @SethMilliken in #41
• More robust sync by @dani84bs in #44
• perf: in annotations modify event only handle docs once by @SethMilliken in #42

Full Changelog: v0.9.99999...v0.9.999999