With the v2→v3 migration sweeping stale `__run__*` branches off `__manifest`
on first read-write open, the defense-in-depth `is_internal_run_branch` guard
is no longer needed.
- delete `db/run_registry.rs`; drop the module + re-export from `db/mod.rs`
- collapse `is_internal_system_branch` to the schema-apply-lock check only
- `ensure_public_branch_ref`: drop the run-ref rejection; `__run__*` is now an
ordinary branch name
- `branch_merge`: reject `is_internal_system_branch` (was run-only) so the
schema-apply lock is rejected consistently with create/delete — a small,
deliberate tightening
- update the inline schema-apply test + the writes integration tests
(`public_branch_apis_reject_internal_run_refs` →
`public_branch_apis_reject_internal_system_refs`, which also asserts
`__run__*` now creates successfully)
- docs: flip the "pending production sweep / defense-in-depth" notes to
"auto-swept by the v2→v3 migration"; document the read-only-open limitation
Known residual: the inert `_graph_runs.lance` / `_graph_run_actors.lance` bytes
remain until a `StorageAdapter::delete_prefix` primitive lands.
The Run state machine was removed in MR-771 (v0.4.0); `docs/dev/runs.md`
and `crates/omnigraph/tests/runs.rs` have since documented and tested the
direct-publish write path, so the "runs" name was misleading.
- git mv docs/dev/runs.md → docs/dev/writes.md (reframe H1 + intro;
keep MR-771 history note)
- git mv crates/omnigraph/tests/runs.rs → tests/writes.rs (reframe header)
- repoint every runs.md / runs.rs reference across docs, AGENTS.md, and
source comments
- fix four pre-existing broken `docs/runs.md` links (the file never lived
at that path) to `docs/dev/writes.md`
- fix the stale v0.4.0 anchor to the live section
No behavior change: every source edit is a comment. Engine builds and the
renamed test passes 25/25; scripts/check-agents-md.sh passes.
The run-removal cleanup itself (run_registry.rs guard, __run__ prefix) is
deferred to MR-770.
