Symphony v0.1.7

What's Changed

• [codex] fix retro release imports by @anantjain-xyz in #93
• [codex] fix retro report wrapping by @anantjain-xyz in #94
• [codex] fix last activity timestamps by @anantjain-xyz in #95
• Kill the whole agent process group on cancel/timeout by @anantjain-xyz in #96
• Add opencode as a fourth agent backend by @anantjain-xyz in #98
• [codex] bump version to 0.1.7 and add bump-version skill by @anantjain-xyz in #99

Full Changelog: v0.1.6...v0.1.7