Registered as /api/backup-target inside ServeStorageAPI, which main.go mounts ONLY
at /api/storage/. Live result: endpoint not found, while every unit test passed --
the tests called the handlers directly and never travelled the mount. Caught by
the first live call, which is why the live call is part of the procedure.
Moved to /api/storage/backup-target[/assign]. A new test asserts the dispatcher
source contains both paths, so a handler nothing routes to fails the suite --
the seam-wiring rule applied to a route rather than a button.
The half that makes the rest work: a degraded backup target recorded only in
config is the silent-degradation pattern this arc has spent a week removing.
Part 3 -- POST /api/backup-target/assign moves the target via the agent's
POST /backup/target. It is the ONLY writer of the role: registration does not set
it, the drive-gate does not, no scheduler does. Declining is not calling it. The
agent returns restart_required rather than restarting itself, because restarting
with a backup in flight records a spurious tier failure for a backup that
actually succeeded (E-1 did exactly that).
Part 4 -- GET /api/backup-target returns the state and, when degraded, Hungarian
copy in FACT -> CONSEQUENCE -> REMEDY order, pinned by a test: a customer told
only the fact cannot act on it.
Healthy renders NOTHING -- no badge, no reassurance, no tonal change.
degradedMessageFor is the single decision point, so exactly one place could start
decorating a working box. Red-proofed: reassuring on the healthy branch fails
Scenario E.
UNKNOWN is not degraded: an unreachable or pre-R-82 agent means we could not ask,
which is not evidence of degradation (R-88 Part 2's class).
A HOLLOW TEST caught by its own red-proof: TestUnknownStateRendersNothing used
{Known:false} with Degraded left false, so it passed even with the !Known guard
deleted -- the second condition covered for it. Now {Known:false, Degraded:true},
which fails properly. Without the red-proof the test would have been decoration.
State is derived from the AGENT, never from our intent flag: on the two boxes
migrated by hand in E-1 the intent was never recorded while the drive really is
the target.
MinAgent: 0.113.0
Green gate: build + vet + test rc=0 (27 packages), run separately from this commit.