atproto git client

feat(plan)!: replace TODO.md with one file per epic master

TODO.md had become 3,400 lines in fifteen sections that named command families rather than lines of work, with a decision record, a bug report and a one-line wish all wearing the same checkbox. Every entry now lives in the epic that covers it, verbatim: thirty-two epics, each carrying an exit criterion somebody could check, its open work above a trailing `## Done`, and frontmatter that plan/README.md's five tables and plan/milestones.md's narrative are read against. Two prek hooks keep the register from drifting from the files it points at, and two entries did not survive the move, both superseded by work that landed under another entry and both recorded as such. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Change-Id: Ia8da43fbb65b5e1277a25eeb8cb8df05f3d08cfa