chore: prepare 1.3 cleanup on restored main

[ebursztein]

Summary

• preserves the repaired main history while applying the trusted 1.3 cleanup tree
• removes the retired PolicyCallback/callback event-type rail so SecurityEvent uses RuntimeSecurityEventType directly
• deletes stale positive Policy V2 E2E tests and keeps stale event strings only in rejection tests
• updates security action benchmarks to exercise SecurityRuleSet/plugin paths

Verification

• cargo check -p capsem-core --no-default-features
• cargo check -p capsem-service --no-default-features
• cargo test -p capsem-core --no-default-features security_event --lib
• cargo test -p capsem-logger --no-default-features security_rule --lib
• cargo test -p capsem-service --no-default-features --lib
• cargo test -p capsem-core --no-default-features --lib
• cargo test -p capsem-logger --no-default-features --lib
• cargo check -p capsem-core --no-default-features --bench security_actions

Notes

The first commit is a merge-style snapshot: parent one is repaired origin/main, parent two is release/1.3-cleanup-pr, and the tree starts from the trusted cleanup branch. The follow-up burn pass removes the stale callback event identity layer instead of preserving compatibility.

[codecov-commenter]

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