chore(main): release 3.12.0

[jmagar]

🤖 I have created a release beep boop

3.12.0 (2026-08-09)

Added

• add cursor event feed and Docker lifecycle forwarding (#185) (26a85b8)
• agent observatory schema foundation + transcript-forwarding env rename (#173) (61aa50a)
• implement Agent Observatory foundation, projection, and Git observation (#160) (6d3031d)

Fixed

• ci: pin kache 0.13.0 to match the runner fleet (#178) (04cbd51)
• ci: remove expression syntax from the s3-endpoint description (#184) (74c2db7)
• ci: remove leaked internal identifiers from setup-rust-kache (#183) (02e3e7f)
• ci: require complete Kache S3 configuration (#186) (d50e1af)
• ci: route .github/actions changes through the full CI matrix (#180) (b8e6900)
• mcpb: add Windows bundle packaging (#164) (a304469)
• mcp: centralize Registry publication (#171) (b731ec3)
• mcp: return structured errors and exact contracts (#170) (287417c)

Changed

• ci: emit line-tables-only debuginfo in dev builds (#182) (1094384)

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[jmagar]

🤖 Created releases:

• v3.12.0

🌻