fix: make the architecture and documentation rules say what is actually true

Three boundaries the layer contract declares had no executable rule behind
them, so the code drifted across all three while every gate stayed green.

`src/contracts` reached back up into `src/application` for the shared `Result`
carrier and the compatibility predicate. Neither package owned the shared
vocabulary and the dependency pointed both ways. Both now live in contracts —
the lower package — and application re-exports them, so no caller moves.

A concrete adapter was not supposed to depend on another concrete adapter, but
only adapter-to-presentation was enforced, and `diagnostics` imported a guard
out of `telemetry`. The guard belongs to neither, so it moved to the adapter
kernel. Stating the rule needed the checker to resolve `$1` in a `to` pattern
against the importing module's own directory; the alternative is one rule per
adapter group, which silently stops covering a group the moment one is added.

Product assembly leaks out of bootstrap: generic presentation reads the
installed-feature registries. That is a real refactor, so the rule freezes the
exact set of modules doing it today rather than pretending it is fixed — a new
edge fails. The two remaining open edges are named in the config, not silent.

Each rule was verified by introducing the violation it forbids and confirming
the gate rejects it.

The documentation drifted the same way. README and the manual accessibility
checklist both said six routes while ten were registered, which left the
platform overview and three reference-resource screens outside the declared
manual review scope without anyone deciding they should be. The scope is now
derived from the route registry by `verify:documentation`, so the sentence
cannot outlive the registry again. The review ledger also named a canonical
path that does not exist in this tree; it is upstream provenance, and it now
says so instead of looking like a broken repository reference.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/architecture/layers.md

@@ -17,11 +17,33 @@ The following edges are forbidden:
 
 - domain to application, presentation, adapters, bootstrap, React, or browser globals
 - application to presentation, concrete adapters, bootstrap, React, or browser globals
+- `contracts` to application or features: contracts is the lower package and
+  owns the shared vocabulary both of them read
 - presentation to concrete adapters, raw DTO schemas, or storage implementations
+- generic presentation to the installed-feature registries: which features exist
+  is a product decision owned by `bootstrap`
 - an adapter to presentation, bootstrap internals, or another concrete adapter
 - feature domain/application to its presentation or outbound adapter, and
   feature presentation to its outbound adapter
 
+## The adapter kernel
+
+"Another concrete adapter" excludes the adapter kernel, which is shared on
+purpose and is the only adapter code an adapter may reach across a group for:
+
+- `src/adapters/platform/**` — the system clock, the shared abort primitive and
+  the bounded-capacity guard
+- `src/adapters/browser-file-storage/result.ts` — the browser-data result and
+  failure constructors
+
+Each rule above is enforced by `check:architecture`, including the kernel
+carve-out, so this table and the executable rules cannot drift apart. Two edges
+are still open and are named explicitly in `.dependency-cruiser.json` rather
+than left silent: the generic presentation modules that read the installed
+registries today, and the two collaborator types `query-cache` reads from
+`cross-context-invalidation`. Both lists are frozen — a new edge of either kind
+fails the gate.
+
 `bootstrap` contains composition only. Business rules and page-specific
 orchestration belong to domain/application.