spec(SHARD-WP-0005 T6): orthogonal core spectra + implied positions + interaction subset (§6.5)

Fixes D-1. ~6 independent core axes (substrate, write-granularity, opacity,
envelope, access, liveness) with the rest implied via published rules that
forbid impossible profiles; a small named axis-interaction table is the
degradation contract (proof obligation behind 'core logic written once').

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

spec/CoreArchitectureBlueprint.md

@@ -262,6 +262,51 @@ only via export→files (I-12).
 - **Absence is first-class** — the profile must express *can't* cleanly (Oddmuse floor), so
   degradation paths are explicit, never guessed.
 
+### 6.5 Orthogonal core, implied positions, and the interaction subset
+
+Fifteen independent ordinal axes is *descriptively* right but would be *operationally* a mess
+if treated as fifteen free dimensions: the axes are **not orthogonal**, and a degradation
+function over all 15 jointly is the flat-checklist problem returning in higher dimensions
+(review D-1). Three rules tame it.
+
+**(a) A small orthogonal core; the rest are implied.** Most axes are *correlated* and collapse
+to a few independent choices. The **core axes** an adapter must independently declare:
+
+1. **Substrate** → drives attachment-mode, history, merge, and native-query positions together
+   (git-IS-store ⟹ history=git-native ⟹ merge=git/text ⟹ query=build-your-own-index;
+   relational-DB ⟹ direct-DB attach ⟹ DB-version-row history ⟹ DB query).
+2. **Write granularity** → drives addressing granularity and the overlay/patch shape.
+3. **Content opacity** → drives translation and (where encrypted) collapses native-query.
+4. **Operational envelope** → drives freshness mode (§8.8) and rebuild expectations (§8.7).
+5. **Access grant** → independent (authz, L5).
+6. **Computational/liveness** → independent (projection kind, §8.5).
+
+The remaining axes are **implied/derived** from these via published implication rules; an
+adapter *may* override an implied position, but the default is computed, not hand-set. This
+turns ~15 free dimensions into ~6 independent ones plus derivations — fewer things to get
+wrong, and impossible combinations become unrepresentable.
+
+**(b) Implication rules forbid impossible profiles.** E.g. `attachment=git-IS-store ⟹
+history≥git-native`; `opacity=encrypted-whole-shard ⟹ native-query=none ∧ translation≤opaque`;
+`merge=native-CRDT ⟹ history=CRDT-log ∧ envelope=realtime`. A profile that violates an
+implication is rejected at registration — capability-as-data (I-3) with integrity constraints.
+
+**(c) The degradation function reads a *named, small* interaction subset — not all pairs.**
+"No per-backend code" is only credible if we say *which* axis interactions the generic logic
+actually consults. They are:
+
+| Operation | Axes consulted (jointly) |
+|-----------|--------------------------|
+| **write / overlay-apply** | write-granularity × merge-model × history × access-grant |
+| **transclude / address a span** | addressing-granularity × write-granularity × identity-vs-placement |
+| **project / cache** | operational-envelope × computational-liveness × content-opacity |
+| **query** | native-query × content-opacity (encrypted ⇒ derive-index-or-none) |
+| **translate** | translation × content-opacity × structure |
+| **federate** | substrate × history × merge (per the §8.3 model) |
+
+Everything else is a single-axis check. This table *is* the degradation contract: it is small,
+enumerated, and testable — the proof obligation behind "core logic written once."
+
 ---
 
 ## 7. Top waist — the Wiki Page Model (L2)

workplans/SHARD-WP-0005-architecture-hardening.md

@@ -129,7 +129,7 @@ operational expectation).
 
 ```task
 id: SHARD-WP-0005-T5
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "b031715c-00d0-4a0a-99f1-4e74a236d04b"
 ```