docs(plans): record all opened S30 step MRs in the Status table

The S30 Maven virtual Status table has a single writer, so the rows for every opened step MR land here instead of in each step's own MR. Every row of the table is filled.

Step	MR
1 — maven_virtual_repositories schema	!2697 (merged)
2 — maven_virtual_repository_upstreams schema	!2719 (merged)
3 — maven_virtual_upstream_rules schema	!2758 (merged)
4 — datastore reads for the upstream list and rules	!2769 (merged)
5 — hosted upstream lookup	!2702 (merged)
6 — remote upstream lookup and prober	!2703 (merged)
7 — Maven coordinate and rule adapter	!2690 (merged)
8 — resolver virtual tier	!2737 (merged)
9 — virtual dispatch slot	!2767 (merged)
10a — memo adapters and the health reader	!2808 (merged)
10b — the wrong-format data-error mark	!2848 (merged)
10c — upstream assembly and the fail-closed gates	!2862 (merged)
11a — error mapping	!2892 (merged)
11b — resolution facade	!2914 (merged)
12 — streaming metadata merger	!2691 (merged)
13 — collection over positions	!2901 (merged)
14 — merged serve surface	!3045 (merged)
15 — composition root	!2947 (merged)
16a — merge memory cap	!2692 (merged)
17 — winner-path artifact and metadata handler	!3002 (merged), !3003 (merged)
18 — sidecar handler by parent shape	!3081 (merged)
19a — winner-path observability	!3014 (merged), !3015 (merged)
19b — merge-path observability	!3088 (merged)
20 — end-to-end harness and e2e catalog	!3087 (merged)

Steps 17 and 19a each landed as two MRs, and their rows name both.

Tracked-by #289 (closed)