Summary

• Bump version from 0.15.2 to 0.15.3
• Update CHANGELOG.md with release notes (fixed: ACP config fallback, TUI metrics, graph metrics; added: OAuth for MCP, code indexing progress, behavioral learning, context compression overrides, orchestration metrics)
• Update all documentation version references
• Update test count badge: 5988 → 6127

Checklist

• Version updated in all manifests (Cargo.toml, Cargo.lock)
• CHANGELOG.md has release section with date
• All documentation updated (mdBook, README, examples)
• All CI checks pass (format, clippy, tests: 6127 passed)
• Ready for tagging after merge

Changes

Commits:

1. release: prepare v0.15.3 — version bump, Cargo.lock, CHANGELOG, snapshot updates
2. docs: update for v0.15.3 release — README badges, installation examples, changelog, ACP/IDE docs

Files changed:

• Cargo.toml (version: 0.15.2 → 0.15.3)
• Cargo.lock (dependency resolution)
• CHANGELOG.md (release section + comparison links)
• README.md (test badge: 5988 → 6127)
• book/src/changelog.md (release notes summary)
• book/src/getting-started/installation.md (version example)
• book/src/advanced/acp.md (version examples)
• book/src/guides/ide-integration.md (version examples)
• Snapshot updates (config and TUI splash widget)