Add Swift support to CodeQL integration

[pruiz]

CodeCome currently treats Swift as unsupported by the local CodeQL integration because the pack catalog and language capability metadata do not include Swift query packs yet. Phase 1a should mention detected Swift code in notes rather than adding it to codeql-plan.yml analysis languages.

Swift appears to be supported upstream by CodeQL, so we should add first-class support when we can validate pack names, build modes, and extraction behavior in our sandbox/recipe flow.

References:

• https://codeql.github.com/docs/codeql-language-guides/codeql-for-swift/
• https://docs.github.com/en/code-security/reference/code-scanning/codeql/codeql-queries/swift-built-in-queries
• https://codeql.github.com/codeql-query-help/swift/
• https://github.blog/changelog/2026-06-05-codeql-2-25-6-adds-swift-6-3-2-support-and-improves-c-coverage/

Acceptance criteria:

• Add Swift to templates/codeql-packs.yml with validated official pack references.
• Add Swift to tools/codeql/capabilities.py with supported build modes.
• Update templates/codeql-plan.yml and prompts/phase-1a-profile.md allowed-language guidance.
• Add runner/gate tests covering Swift plans under soft and hard fail policies.
• Validate at least one sandbox-backed Swift target end-to-end.