The docs stop calling built things "not yet": custom domains, landing on green, a proposal's nod and feed paging #7224

The four docs now say what is built, each naming its module. test/cluster-doc.test.ts and test/mcp-size.test.ts pass, as do the 101 tests scripts/fast.ts named. I did not run bun x tsc --noEmit, since the change is docs only.

• docs/STATUS.md and docs/ARCHITECTURE.md:

- Both now say app processes run in bubblewrap cells (src/apps/contain.ts), apps take custom domains (MCP app_domains, src/http/mcp/tools/app_domains.ts), and a pull lands on its own once review and checks agree (src/checks/landing.ts, src/checks/queue.ts). - They still list "a package registry" as not built; I found nothing for it in src. - docs/ARCHITECTURE.md also keeps "federation beyond signing in through a parent forge (src/core/federation.ts)". I found only parent sign-in and mirrors, nothing broader.

• docs/PLANNING.md: a person's nod opens a stored proposal, through approve in src/actions/proposals.ts, from the inbox card or the MCP asks_proposal. The same section also said "nothing reads a stored proposal yet", which was stale, so I reworded it. With plansNeedNod on, the planner's work now waits for the nod.
• docs/FEED.md:

- It no longer says paging past the first 20 is missing: ?cursor= pages in src/web/studio/feed.ts. - It also dropped two other "not yet" items. The choose card now comes from src/feed/choose.ts, and run cards offer Stop in src/web/studio/cards.ts.

grep -rn "not yet\|not built" docs still turns up other lines, but none of them are about these four things. I left them alone.

Closes #7209

The four docs now say what is built, each naming its module. test/cluster-doc.test.ts and test/mcp-size.test.ts pass, as do the 101 tests scripts/fast.ts named. I did not run bun x tsc --noEmit, since the change is docs only.

• docs/STATUS.md and docs/ARCHITECTURE.md:

- Both now say app processes run in bubblewrap cells (src/apps/contain.ts), apps take custom domains (MCP app_domains, src/http/mcp/tools/app_domains.ts), and a pull lands on its own once review and checks agree (src/checks/landing.ts, src/checks/queue.ts). - They still list "a package registry" as not built; I found nothing for it in src. - docs/ARCHITECTURE.md also keeps "federation beyond signing in through a parent forge (src/core/federation.ts)". I found only parent sign-in and mirrors, nothing broader.

• docs/PLANNING.md: a person's nod opens a stored proposal, through approve in src/actions/proposals.ts, from the inbox card or the MCP asks_proposal. The same section also said "nothing reads a stored proposal yet", which was stale, so I reworded it. With plansNeedNod on, the planner's work now waits for the nod.
• docs/FEED.md:

- It no longer says paging past the first 20 is missing: ?cursor= pages in src/web/studio/feed.ts. - It also dropped two other "not yet" items. The choose card now comes from src/feed/choose.ts, and run cards offer Stop in src/web/studio/cards.ts.

grep -rn "not yet\|not built" docs still turns up other lines, but none of them are about these four things. I left them alone.