`topology.json` was a map of `name -> parent | null`, and that value fed
the whole agent hierarchy: `<parent>` / `<children>` recipient sentinels,
the reparenting API (CLI verb, wire verb, dashboard endpoints, DAG node),
the dashboard tree, the rebuild depth sort, and an unconditional
bind-mount grant giving every agent RW on its direct children's state.
Per the operator's ruling the field goes, and with it all of the above.
The file survives as what remains once the value is gone: the roster of
agent names, which is the set `ManageRootAgent` grants mounts over. It is
now a JSON array; `read` still accepts the old map shape and keeps its
keys, so a hive that upgrades across this does not blank its roster (and
so no capability holder loses its mounts for the length of that window).
Two sites kept their behaviour under a different recipient rather than
losing it. Both addressed `<parent>`, which the broker already resolved to
`operator` for a root agent, and every agent is now what that fallback
called a root:
- the harness's turn-failure / plugin-failure notification
(`Surface::send_to_parent` -> `send_to_operator`), and
- the send allow-list's always-permitted escape hatch, so an agent with a
restrictive allow-list still has a way to say it is stuck.
What is NOT preserved, deliberately: an agent with no capability no longer
sees any other agent's dirs. `ManageRootAgent`'s own grant is unchanged --
still every agent in the roster, still state RW + config RO, still no
`harness`.
The dashboard's reparenting control (the M0V3 picker) is deleted with its
CSS. The tree rendering that reads `ContainerView.parent` is left for the
frontend owner -- it degrades to a flat list with the field gone.
Closes the #3110 split — lib.rs is now just the crate doc comment and
the pub mod list.
journal.rs's new doc comment fixes a pre-existing bug: the old
JournalPriority doc text in lib.rs was actually half Capability's doc
(a leftover from an earlier reorder that moved the code but not the
comment above it).
Replace the try-and-ignore-duplicate-column approach in apply_migrations
with proper schema versioning using a shared schema_versions table.
## mechanism
New function: db::apply_versioned_migrations(conn, subsystem,
legacy_column, migrations). Tracks the applied-migration count in a
schema_versions table (one row per subsystem key). Only migrations past
the stored version run.
Legacy detection: pre-versioning databases have no schema_versions row.
The legacy_column tuple (table, column) identifies a column that exists
only in a fully-migrated legacy database. If present, all known
migrations are skipped. If absent, migrations start from 0.
## stores migrated
- broker: removes bespoke ensure_message_columns / ensure_reminder_columns.
Unified into BROKER_MIGRATIONS (v1-v5). Legacy detector: messages.priority
(added in the last pre-versioning migration).
- approvals: 4 historical migrations (v1-v4). Legacy detector:
approvals.submitter.
- operator_questions: 3 historical migrations (v1-v3). Legacy detector:
operator_questions.target.
- scheduled_prompts: 1 historical migration (v1). Legacy detector:
scheduled_prompts.paused_at_unix.
apply_migrations removed (no callers).
## tests (db.rs)
- fresh_install_runs_all_migrations
- legacy_install_skips_all_migrations
- partial_migration_resumes_from_version
- already_at_latest_is_noop
- multiple_stores_in_same_db
