_insert_session_row never copied cwd/git_repo_root from a parent row when
parent_session_id was set, and git_repo_root wasn't even in the INSERT's
column list. The compression-fork path (and delegate/subagent spawns,
branch continuations) creates a child session without passing cwd/
git_repo_root at all, so the child's tip is born NULL — and since the
Desktop project sidebar groups sessions by cwd, the whole project silently
drops out of the sidebar every time a long conversation compresses. A
lineage that compresses repeatedly compounds this across generations.
Add git_repo_root to _insert_session_row's INSERT/COALESCE-on-conflict
column set, and backfill both cwd and git_repo_root from the immediate
parent row (single non-recursive hop, matching the existing COALESCE
"never overwrite an explicit value" contract) inside the same write
transaction whenever parent_session_id is set. A multi-generation chain
resolves correctly because each generation's own create_session call
already backfills from its (already-resolved) immediate parent.
Fixes#64709
Simplicio, Wesley (ext)
3c74c12554