docs(changelog): cut RoboCo 0.5.0

Promote the Unreleased section to [0.5.0] - 2026-06-16 — AC/decomposition
guardrails, per-dev sequenced code queues, the unified Business page, the 26
panel UI fixes, and the spawn/PR/ownership firefight fixes — and add the 0.5.0
compare link.

Correct the Removed note: the /cockpit, /company-goals, /secretary, and
/pitches panel routes are deleted (404), not redirected; the relocated strategy
signals are served by the new GET /api/cockpit/signals endpoint.

Bump the version 0.2.0 -> 0.5.0 across pyproject, __init__, config app_version,
panel package.json, and the uv.lock self-entry — these had drifted unbumped
since 0.3.0.

panel/package.json

@@ -1,6 +1,6 @@
 {
   "name": "roboco-panel",
-  "version": "0.2.0",
+  "version": "0.5.0",
   "private": true,
   "packageManager": "pnpm@10.25.0",
   "scripts": {