v1.0.0-rc5

No user-facing changes.

• Refactored manifests into base + browser overrides
• Added Firefox extension test suite (WDIO v9) and CI job
• Added Chrome Web Store privacy declarations
• Reorganized test directory structure
• Hardened CI tests for runner variability (retries, timeouts)
• Enabled Dependabot for npm dependency updates
• Updated dependencies

Full Changelog: v1.0.0-rc2...v1.0.0-rc5