release(v0.5.0): Phase 5 close — quota probe + dashboard enrichment (#57)

Promotes "Unreleased" → v0.5.0 — 2026-05-26. Maintainer-triggered per
CLAUDE.md release_kit.phase_close_trigger.

Phase 5 closed with 6 D-days shipped across 7 PRs, every PR through a
fresh-context opus reviewer per Iron Rule 10, 0 blocking findings, 720
→ 756 tests, no flakies, all CI green:

- D79 governance (PR #50): ADR 0012 charter + ADR 0002 Amendment 8 +
  ADR 0013 + ALIGNMENT.md Class-specific Exceptions §1
- D79 cleanup (PR #51): reviewer N6+N7+N9 fold-in
- D80 (PR #52): anthropic plan-usage probe port (~250 LOC; OCP
  server.mjs:842-1109 → lib/providers/anthropic.mjs:quotaStatus())
- D81 (PR #53): lib/audit-query.mjs aggregateProviderQuota() +
  /v0/management/{dashboard-data,quota} quota_v2 field +
  models-registry.json quota_probe block
- D82 (PR #54): dashboard.html Claude.ai-style Plan Usage panel
  (closes v1.x roadmap #8)
- D83 (PR #55): Suite 38 (20 probe unit tests) + Suite 39 (8 dashboard
  smoke tests) + 5 test seams
- Close-prep (PR #56): README § Plan Usage + § Supported Providers
  Quota-probe column + dashboard screenshot + docs/exit-gates/phase-5-e2e.json
  + 3-finding fold-in

Changes in this commit:
- package.json: 0.4.4 → 0.5.0
- CHANGELOG.md: "Unreleased" promoted to "## v0.5.0 — 2026-05-26"
  with comprehensive release notes spanning all Phase 5 deliverables;
  fresh empty "## Unreleased" added above for Phase 6
- CLAUDE.md release_kit.phase_rolling_mode:
    current_phase: Phase 5 → Phase 6
    current_pre_release_identifier: "0.5.0-phase5" → "0.6.0-phase6"

Tag push (git tag v0.5.0 && git push --tags) happens AFTER this merges
to main. Tag push fires .github/workflows/release.yml which auto-creates
the GitHub Release with notes derived from CHANGELOG.md.

Tests: 756/756 pass locally; no production-code changes beyond version
bumps.

Authority: CLAUDE.md release_kit overlay (Iron Rule 5.5); ADR 0012
§ Exit gate (all 9 items satisfied); Phase 5 D-day commits 1605400,
187e793, 82d2e1c, 5288493, a41420d, 2b07a3b, d872330 on main.

Co-authored-by: dtzp555 <dtzp555@gmail.com>
Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "olp",
-  "version": "0.4.4",
+  "version": "0.5.0",
   "description": "Personal multi-provider LLM proxy. Successor to OCP. One HTTP endpoint, multiple subscriptions behind it, automatic routing + fallback + caching.",
   "type": "module",
   "main": "server.mjs",