Accept ADR 0054 (slug) and resolve issue 010

ADR 0054 accepted with option E (a declared slug). Issue 010 resolved: the login fits
via the slug, and the minted secret shrinks to 40 chars for S3's secret-key limit —
both halves of an S3 credential now fit the tightest backend.

Claude-Session: https://claude.ai/code/session_01LrgweAeERJYBg88c5cKDzF

02-DECISIONS/0054-a-consumers-identity-fits-the-tightest-backend.md

@@ -1,5 +1,5 @@
 ---
-status: proposed
+status: accepted
 date: 2026-09-05
 deciders: jochen
 reconstructed: false

04-ISSUES/010-mesh-login-exceeds-s3-access-key-limit/00-report.md

@@ -1,9 +1,9 @@
 ---
-status: open
+status: resolved
 opened: 2026-09-05
 located-in: [mesh-control, mesh-catalog]
-fixed-by:
-amended-design:
+fixed-by: ADR 0054 (a slug for the login) + a shorter minted secret (mesh-control)
+amended-design: 0054-a-consumers-identity-fits-the-tightest-backend.md
 ---
 
 # The mesh's derived login does not fit every backend's identity rules — S3 rejects it
@@ -62,6 +62,16 @@ and those are not always the same string.
   permissive? If nothing needs it long, the cheap fix is to cap it.
 - Does this fold into the same decision as the data-provision return path, or is it separate?
 
-The options are sketched in **ADR 0054 (proposed)** — bound the identity by the true minimum and
-refuse early (recommended), a compact fallback for overflow, per-interface bounds, or a
-provider-generated identity (rejected). Awaiting ratification.
+## Resolution
+
+Accepted **ADR 0054** (option E): a module declares an optional short `slug`, and the mesh derives
+`mesh_<node>_<slug|name>`, bounded by the tightest backend (an S3 access key's 20) and refused at
+assignment — naming the slug as the remedy — when it still would not fit. The minio grant e2e proved
+it: `bucketuser` declares `slug: bkt`, so its access key `mesh_anchor_bkt` (15) is accepted where
+`mesh_anchor_bucketuser` (22) was refused.
+
+Proving that surfaced a **second S3 length constraint on the same credential** — the secret. The
+mesh minted a 43-character password (32 random bytes, base64url), and an S3 secret key is 8–40. Fixed
+in `mesh-control` `internal/secrets/seal.go` by minting 30 bytes → exactly 40 characters (240 bits,
+ample), which fits S3 and every other backend. Both halves of an S3 credential — the access key
+(login) and the secret key (password) — now fit the tightest backend, by the same rule.