feat(#1416): formalize Resolution convention + agent-skills value envelope (Resolution Provenance P3) (#1425)

Narrows P3 of ADR-1411 (Resolution Provenance, epic #1411) based on an
adversarial fit-analysis that showed a single Resolution<T> envelope adopted
by agent-skills, capability-state, and capability-writer fails the deletion
test: configured/reason are meaningless for capability verbs, and
capability-writer's errors[] (operation-not-applied) cannot fold into
warnings[]. The only genuinely shared seam is warnings: string[].

Changes:

- src/resolution.cts: new pure types+builder leaf — exports Resolution<T>
  {value, configured, reason, warnings}, makeResolution<T>() builder, and
  AgentSkillsValue {block, skills_count}. No other src/ imports.

- src/init.cts: cmdAgentSkills --json IR gains additive value:{block,
  skills_count} field (built via makeResolution). All existing flat fields
  (agent_type, block, skills_count, warnings, configured, reason, source,
  degraded) are retained unchanged for back-compat.

- src/capability-state.cts: doc comment on ResolveCapabilityRuntimeStateResult
  naming it the canonical read-verb envelope. No JSON change.

- src/capability-writer.cts: doc comment on SetCapabilityStateResult naming it
  the canonical mutation-verb result (warnings=advisory, errors=operation-
  not-applied). No JSON change.

- CONTEXT.md: new ### Resolution Convention glossary entry after
  ### Resolution Provenance.

- docs/adr/1411-resolution-provenance.md: P3 narrowing amendment appended.

- tests/resolution.test.cjs: 9 unit tests for makeResolution (new).
- tests/agent-skills.test.cjs: 2 P3 tests for value.block/value.skills_count
  and back-compat of all flat fields.

All 277 tests pass (5 suites). npm run lint clean. All lint checks pass.

Part of #1411

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

docs/INVENTORY-MANIFEST.json

@@ -350,6 +350,7 @@
       "prompt-budget.cjs",
       "research-provider.cjs",
       "research-store.cjs",
+      "resolution.cjs",
       "review-reviewer-selection.cjs",
       "roadmap-command-router.cjs",
       "roadmap-parser.cjs",

docs/adr/1411-resolution-provenance.md

@@ -75,3 +75,15 @@ Rejected. Fixing cwd/workstream drift removes the most common trigger but leaves
 - **Supersedes** the tactical fix in PR #1408 (closed) — its `resolvePlanningCwd` and local `AgentSkillsReason`/`AgentSkillsDiagnostics` are redelivered through the seams above in P1–P3.
 - **Builds on:** ADR-227 (input validation shape), ADR-0004 (Planning Workspace Module), ADR-0006 (Planning Path Projection Module).
 - **Prior recurrences of this class:** #1374/#1376, #1683, #991, #2714, #2638, #3523, #2652, #2791, #2555, #2623, #3196.
+
+## Amendment — 2026-06-18: P3 narrowed (the shared envelope is not a real seam)
+
+The original P3 plan was a single `Resolution<T> { value, configured, reason, warnings }` envelope adopted by `agent-skills`, `capability-state`, and `capability-writer`. An adversarial fit-analysis showed this fails the deletion test: `configured`/`reason` are meaningless for the capability read/mutation verbs, and `capability-writer`'s `errors[]` (operation-not-applied) is load-bearing and cannot fold into `warnings[]` (advisory). The only genuinely shared seam across the three is `warnings: string[]`.
+
+P3 is therefore narrowed to an honest convention rather than a forced generic:
+
+- `Resolution<T> { value, configured, reason, warnings }` (`src/resolution.cts`) is the canonical shape for **config-interpreting read verbs**. `agent-skills` is the first adopter — the `value` field is added additively to its `--json` IR with the flat fields retained for back-compat; `source`/`degraded` remain config-provenance extras.
+- Capability verbs keep their existing shapes, named explicitly: read = `{ runtimeConfigDir, capabilities, warnings? }`; mutation = `{ capabilities, warnings, errors }`.
+- The shared contract is documented, not forced: read verbs expose `warnings[]`; mutation verbs expose `warnings[]` + `errors[]`; `configured`/`reason` appear only on config-interpreting read verbs.
+
+Recurrence prevention does not depend on a shared envelope — it is delivered by P4's CI guard (a configured input resolving empty must carry a `reason`). (#1416)