Phase 2b: desktop sidecar (build but do not publish)

[antarr]

Summary

• Adds gems/mysql_genius-desktop (version 0.1.0): a Sinatra + Trilogy sidecar that serves the shared MysqlGenius dashboard against any MySQL/MariaDB server configured via local YAML. First non-Rails consumer of mysql_genius-core 0.6.0.
• Adds Core::Connection::TrilogyAdapter (reopens Core::Connection namespace from the desktop gem, same pattern as ActiveRecordAdapter in the Rails gem).
• Adds capability?(name) helper to SharedViewHelpers + template guards around the three Redis-backed features (slow_queries, anomaly_detection, root_cause). Rails adapter always reports :slow_queries as a capability, so nothing visible changes for Rails host apps.
• No RubyGems release. mysql_genius-desktop stays in-repo at 0.1.0. .github/workflows/publish.yml is untouched. Both mysql_genius and mysql_genius-core stay at 0.6.0 — no version bump, no tag, no publish fire.

Test plan

• Rails adapter suite green (78 examples including 2 new capability regression guards)
• Rails adapter rubocop clean (135 files)
• mysql_genius-core suite green (194 examples unchanged)
• mysql_genius-core rubocop clean (60 files)
• New mysql_genius-desktop suite green (111 examples: 13 TrilogyAdapter, 22 Config sub-struct, 12 Config loader, 10 ActiveSession, 9 Launcher, 5 index, 3 columns, 5 execute, 3 explain, 7 analysis, 12 AI features, 3 redis 404, 7 capabilities)
• New mysql_genius-desktop rubocop clean (36 files)
• New desktop CI job runs green on the PR
• Manual end-to-end: TESTING.md recipe against local MySQL 8.0 in Docker — every tab renders, Slow Queries / Root Cause / Anomaly UI confirmed hidden, unregistered routes 404

See docs/superpowers/specs/2026-04-12-phase-2b-desktop-sidecar-design.md for the full design.

[gitguardian]

⚠️ GitGuardian has uncovered 2 secrets following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secrets in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
30214789	Triggered	Username Password	11e6902	gems/mysql_genius-desktop/spec/mysql_genius/desktop/config/mysql_config_spec.rb	View secret
30214789	Triggered	Username Password	634895e	gems/mysql_genius-desktop/spec/mysql_genius/desktop/config_spec.rb	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secrets safely. Learn here the best practices.
3. Revoke and rotate these secrets.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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^{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}