refactor(linkedin-studio): move agent fasit fixtures + tests out of agents/ (v0.5.3)

The 6 long-form-review fasit fixtures (agents/fixtures/*-cases.md) were registered
by Claude Code as junk `fixtures:*` agents because agents/ is scanned recursively.
They are test fixtures, not capabilities. Moved them + their 6 lint tests to
tests/ + tests/fixtures/ and retargeted the 5 agent fasit-refs. Count-neutral
namespace hygiene (ls agents/*.md still 19).

- agents/fixtures/*-cases.md            -> tests/fixtures/        (6)
- agents/__tests__/*-fixture.test.mjs   -> tests/                 (6; ../fixtures -> ./fixtures)
- 5 agent refs ${CLAUDE_PLUGIN_ROOT}/agents/fixtures -> /tests/fixtures
- version-sync 0.5.2 -> 0.5.3 (plugin.json / README badge / CLAUDE.md / CHANGELOG)

Verify: fixture-lint 35/35 at new path; render 20/20, hooks 139/139; test-runner 109/0/0.
Reinstall/reload required for the 6 spurious agents to leave the registry.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CrTb8ktf1XZWEVwgz5MTTo

tests/editorial-reviewer-fixture.test.mjs

@@ -0,0 +1,87 @@
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+
+// Lint-test for the editorial-reviewer fasit fixture.
+// Mirrors the structure-only discipline of persona-reviewer-fixture.test.mjs and
+// fact-checker-fixture.test.mjs: this test asserts the SHAPE of the fixture —
+// the two judging axes, all ten checks (P1–P5 + A1–A5), the three severities,
+// and the eight Del 4 cases that form the gold standard. Whether the agent's
+// live flags actually reproduce the fasit directions is [GATE]/[OPERATØR],
+// never self-certified here.
+
+const FIXTURE_PATH = fileURLToPath(
+  new URL('./fixtures/editorial-reviewer-cases.md', import.meta.url)
+);
+
+const fixture = readFileSync(FIXTURE_PATH, 'utf8');
+
+// The ten checks: five prose-craft (P1–P5) + five narrative-architecture (A1–A5).
+const PROSE_CHECKS = ['P1', 'P2', 'P3', 'P4', 'P5'];
+const ARCH_CHECKS = ['A1', 'A2', 'A3', 'A4', 'A5'];
+
+// The two axis names (Norwegian, as the agent and the writing contract use them).
+const AXES = ['prosa-håndverk', 'narrativ-arkitektur'];
+
+// The three-rung severity scale.
+const SEVERITIES = ['BLOCK', 'REWORK', 'NICE'];
+
+describe('editorial-reviewer fixture structure', () => {
+  test('names both judging axes', () => {
+    for (const axis of AXES) {
+      assert.ok(
+        new RegExp(axis, 'i').test(fixture),
+        `fixture must name the axis "${axis}"`
+      );
+    }
+  });
+
+  test('documents all ten checks (P1–P5 + A1–A5)', () => {
+    for (const check of [...PROSE_CHECKS, ...ARCH_CHECKS]) {
+      assert.ok(
+        fixture.includes(check),
+        `fixture must reference the check "${check}"`
+      );
+    }
+  });
+
+  test('defines the three-rung severity scale', () => {
+    for (const sev of SEVERITIES) {
+      assert.ok(
+        fixture.includes(sev),
+        `fixture must define the severity "${sev}"`
+      );
+    }
+  });
+
+  test('documents the eight Del 4 cases', () => {
+    const cases = fixture.match(/^###\s+Case\s+\d+\b/gim) || [];
+    assert.equal(
+      cases.length,
+      8,
+      `fixture must document exactly 8 Del 4 cases (found ${cases.length})`
+    );
+  });
+
+  test('ties the checklist to the Maskinrommet §C2 truth source', () => {
+    assert.ok(
+      /§C2|C2/.test(fixture),
+      'fixture must reference the §C2 writing-contract truth source'
+    );
+  });
+
+  test('keeps the jury-judges-writer-writes boundary (direction, not copy)', () => {
+    assert.ok(
+      /direction, not rewritten copy/i.test(fixture),
+      'fixture must state the direction-not-copy boundary'
+    );
+  });
+
+  test('records the persona-blindspot rationale (≈6/8 editorial-only)', () => {
+    assert.ok(
+      /blindsone/i.test(fixture) && /6\/8/.test(fixture),
+      'fixture must record why the gate exists (blind spots, ~6/8 editorial-only)'
+    );
+  });
+});