docs: this repo is public, so say what things are, not who decided them

Comments and served API descriptions here had grown references that only make
sense to someone with our internal notes: relative paths that escape this
tree, filenames and titles of documents nobody outside can open, quoted prose
from them, and the name of a component that has no public surface — once in an
OpenAPI description, which is published output rather than source.

None of it was load-bearing. Every case restates as what the code actually
requires, and every rewrite came out shorter: "in the words the host agent
reports" for a component name, "republished as addresses are discovered" for a
quoted phrase, "a size tier sets vCPU, RAM and the output geometry" for a
sentence that had been carrying a path.

Internal reasoning is now cited exactly one way, ref(d-NNNN) in a source
comment, with the rule that the sentence must still stand if the marker is
deleted. CLAUDE.md leads with it, because the previous version of this mistake
was made by people who knew the repo was public and it still took ten
occurrences to notice, so "be careful" is not a mechanism.

Commit messages get the stricter rule and carry no references at all: a
comment can be fixed by the next commit and a published message cannot be
fixed at all. Git hooks now enforce both halves.

The check caught a real one while being written: the CLAUDE.md table spelled
out the paths it was prohibiting, which discloses them to exactly the reader
it protects against.

138 tests, 0 fail.

packages/core/src/db/fixtures.ts

@@ -6,16 +6,15 @@ import { User } from '../user/index.js';
 import { LinkedAccount } from '../user/linked-account.js';
 
 /**
- * Fixtures for the ownership chain, because since
- * [0048](../../../../.nestri/decisions/0048-email-is-the-root-identity-and-a-box-is-a-row.md)
- * it is a chain rather than a set of loose rows.
+ * Fixtures for the ownership chain, which is now a chain rather than a set of
+ * loose rows.
  *
- * A box now needs a user, a team, and a machine to exist before it can, and a
+ * A box needs a user, a team, and a machine to exist before it can, and a
  * session needs a game and a linked account on top of that. Every test that
  * touches either was otherwise going to build the same four rows by hand, and
- * the version built by hand is the version that quietly uses a `hst_…` string
- * where a real machine id belongs — which is exactly what the new foreign key
- * exists to catch.
+ * the version built by hand is the version that quietly uses a made-up host
+ * string where a real machine id belongs — which is exactly what the foreign
+ * key exists to catch. ref(d-0048)
  *
  * Test-only. Nothing here is imported by shipping code.
  */