ipc: a seed_event method, step-up gated, refused by the store (V-518)

The pattern detector needs four events for one action+object spread by at
least two hours before it proposes a routine. The only writer in the tree is
a fact write at time.Now(), so V-43, V-46, V-247 and V-254 all stopped at the
same missing step. This is the wire half of the seam that unblocks them.

The request takes a fact — key, value, timestamp — not an event, so
pattern.Extract runs for real on the daemon side and a key the extractor
ignores seeds nothing. The response says which of those happened, because a
caller that assumed a seed always yields an event would read four silent
successes as a broken detector.

AuthStepUp, the same rung as mutating the tool allowlist, and not because
backdating is privileged in the usual sense: every other write records when
something happened and this one asserts it. StoreAPI refuses outright — the
method needs the daemon's detect-and-propose step, and a direct store caller
would write a fact and quietly skip it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011x5DgnExQ5XZy8TZPs5bot

internal/ipc/client.go

@@ -487,6 +487,14 @@ func (c *Client) ListProposedRoutines(ctx context.Context) ([]ProposedRoutine, e
 	return r.Routines, nil
 }
 
+func (c *Client) SeedEvent(ctx context.Context, req SeedEventReq) (SeedEventResp, error) {
+	var r SeedEventResp
+	if err := c.call(ctx, MethodSeedEvent, req, &r); err != nil {
+		return SeedEventResp{}, err
+	}
+	return r, nil
+}
+
 func (c *Client) CaptureTask(ctx context.Context, req CaptureTaskReq) (CaptureTaskResp, error) {
 	var r CaptureTaskResp
 	if err := c.call(ctx, MethodCaptureTask, req, &r); err != nil {