ADR 0108: a route carries the policy applied to a request

Issue 116 found the mesh's proxy applies nothing to a request — host lookup, forward. Against
what the replaced ingress actually relies on, four capabilities are missing: authentication
(three dependents, each gating an admin surface with no login of its own), refusal scoped to a
path (one, a live incident mitigation), path-scoped routing with priority, and redirect.

Policy goes on the route rather than beside it. A proxy-side settings layer keyed by route name
would keep the grant literally clean, but then "what protects this route" is answered from two
files nothing keeps in step — and a route's protection is part of what a route is.

The set is closed at those four, so a fifth is an amendment and each addition is earned by a
dependent that exists. An open middleware surface was rejected: it recreates what is being
replaced, and narrowing one later is far harder than widening a closed one.

Where policy needs a credential the declaration names a secret and never carries the value,
which keeps the existing secret machinery the only thing holding credentials. Inlining a hash
was rejected as the first credential in a declaration — a precedent easier to set than withdraw.

This re-keys the routing table by host and path with priority, which follows from the decision
rather than being a separate one: two of the four need one host routed more than one way. Equal
priorities must resolve identically every time or the proxy stops being reproducible.

The record says how it is checked, including the negative case that rots quietly — a
declaration carrying a credential value rather than a reference must be refused, so the
rejected option cannot return by accident.

08-connectivity §3 names the record and gains the subsection; issue 116 gains amended-design.

02-DECISIONS/README.md

@@ -123,6 +123,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0094** — [A module may hold several secrets from one provider, each a pair of its own](0094-a-module-may-hold-several-secrets-from-one-provider.md)
 - **0095** — [The control plane is the way to ask a module](0095-the-control-plane-is-the-way-to-ask-a-module.md)
 - **0098** — [A fact a provider makes at first start is fetched from it, not carried in its manifest](0098-a-fact-a-provider-makes-at-first-start-is-fetched-from-it.md)
+- **0108** — [A route carries the policy applied to a request, and names a secret rather than holding one](0108-a-route-carries-the-policy-applied-to-a-request.md)
 
 ### What runs on them, and how it gets there