feat(memory): connect agents through memory MCP

[delkc]

Summary

Connect supported agents to approved memory through a bundled MCP sidecar.

• Expose list_topics, recall, and consent-gated propose_memory tools
• Register the sidecar with Goose sessions and honor the shared memory policy on every call
• Package and stage the sidecar for macOS, Windows, development, and release builds
• Restrict recall to exact approved topics and reject credential-shaped proposals before queueing
• Teach Berdy to treat memory as user-owned context, never action authority

Related issue

N/A. Depends on #289.

Testing

• MCP protocol, policy, topic matching, proposal, credential, and symlink tests
• macOS and Windows sidecar staging checks
• Rust checks and Clippy

Generated with Goose

[shellz-n-stuff]

Technically vulnerable to similar pathjacking as #273

[daveh-beep]

🤖 Encryption follow-up draft: #347

@delkc this is stacked directly on #290 (base 7aa3392). The memory crate and focused UI tests pass; the draft remains open for the release blockers documented in the PR: signed app/sidecar keystore sharing, legacy plaintext migration, Windows/Linux native acceptance, confirmation of the reviewed import-race finding, and the existing 14 unrelated voice-test failures.