chore: adopt layered agent context

[shivros]

Summary

• Pin Hydra's composed Creed source to reviewed TechGodHQ/agent-context commit d678bf718664cd2f894279350f6a2010015c8af2.
• Regenerate AGENTS.md with shared organization procedures before Hydra-local guidance and remove duplicated local Git/PR policy.
• Update context-drift CI to Creed v0.4.1.

Verification

• Clean-cache released creed@v0.4.1: validate, sync, repeated idempotent sync, and diff.
• Verified layered creed push is rejected.
• cargo build --all-targets
• cargo test --all-targets (57 passed)
• cargo clippy --all-targets -- -D warnings
• cargo fmt --all -- --check
• Hydrа codegen check for examples/notes and examples/security-scan.

Closes COD-446.

[shivros]

🤖 Automated Review Panel

Reviewer A

APPROVE — the pinned layered source preserves Hydra-local context, emits the central policy/procedures, and removes only duplicate local Git/PR policy. Released Creed v0.4.1 validation and all Cargo/codegen gates passed.

Reviewer B

APPROVE — CI now installs Creed v0.4.1 for the drift gate; regenerated AGENTS.md is composed in the required order. No correctness findings.

[shivros]

Auto-Merge Gate

Confidence: 0.94

The pinned, full-SHA layered Creed source, generated context, removal of redundant local policy, and v0.4.1 drift gate directly meet COD-446. Both independent review-panel reviewers approved the change; no unresolved review feedback is present.

Observed checks: Test, Creed context drift — successful.

Scope limits: documentation/context composition and CI drift validation only; no release, deployment, credential, or destructive change.