011: postgres worked through, and "one kind of edge" was wrong

The tidy version said a module provides names and requires names and that is the only edge. Working postgres through completely disproves it. A small game wanting to store data does not require postgres to EXIST. It requires postgres to MAKE IT A DATABASE and hand back credentials. Those are different relations in every way that matters: one creates something per consumer, carries a payload back, can be revoked, and leaves the provider holding state about who was granted what. The other creates nothing. So: two kinds of edge, one graph. Instantiation implies presence; presence does not imply instantiation. The current system already had exactly this split — `dependencies` for presence, `requires: provision:` for instantiation, with the resolver deriving one from the other. analysis.md called that derivation a convenience. It is not: it is the correct relationship between two genuinely different relations, and the design had collapsed them. Postgres also turns out to be nine things, not one. A container. Persistent state where moving nodes is a migration rather than a reschedule. Configuration partly derived from the machine's hardware. A tool surface. A provisioner. Its own bookkeeping about what it granted, which is not the data it stores. An exposure decision per node it runs on. Credentials it generates, which means a provisioning edge carries a secret. And health that is not "the container is up". Four questions the worked example makes concrete rather than abstract. WHICH postgres, when there are two — a consumer of `terminal` does not care and a consumer of a database cares permanently. How many instances a module should have, which cannot be a global rule because one-per-mesh is wrong for a store a disconnected node needs and one-per-node is wrong for the mesh's own registry. What happens to a grant when its consumer is removed, where dropping is data loss and keeping is a leak. And whether a declaration is composed PER NODE from what that node reported — because tuning follows hardware the control plane cannot know, and the alternative is the host deciding, which ADR 0037 forbids.
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 # One kind of edge

+> **Superseded in part by [`worked-postgres.md`](worked-postgres.md).** Working postgres through
+> completely shows there are **two** kinds of edge, not one: *presence* — the thing exists and is
+> reachable, nothing created — and *instantiation* — the provider is asked to make something for
+> this consumer and hands back credentials. Instantiation implies presence; presence does not
+> imply instantiation. Everything else below stands; the claim in the title does not.
+
 A design, not an account of what exists. [`analysis.md`](analysis.md) measured the current
 catalogue and its value here is two lessons rather than its machinery: a field that means
 *depends on* should say so, and placement does not belong in a manifest.