refactor(safe-outputs): reduce complexity of execute_impl in link_github_sub_issue.rs

[github-actions]

What was complex

LinkGithubSubIssueResult::execute_impl in src/safe_outputs/link_github_sub_issue.rs was flagged by Clippy's too_many_lines lint at 190/100 lines — the single highest non-test candidate after the two functions already at the top of the list (create_pull_request.rs and ado_proxy/catalog.rs) had already been processed in prior runs.

The function mixed together several distinct concerns in one long block: config/token validation, resolving and cross-checking the parent/sub-issue targets, fetching and validating GitHub issue metadata, a GraphQL preflight check for an existing parent, and finally performing the addSubIssue mutation and validating its response.

What changed

Extracted four well-named helper functions/methods, each owning one concern:

• LinkGithubSubIssueResult::resolve_targets — resolves the parent/sub-issue targets via resolve_github_issue_target and validates they're in the same repository and are distinct issues.
• fetch_and_validate_metadata — fetches parent/sub-issue metadata and validates target capability + mutation filters.
• check_existing_parent — runs the GraphQL preflight query and returns an early success (already linked to the same parent) or failure (linked to a different parent), or None to proceed.
• link_sub_issue — performs the addSubIssue GraphQL mutation and validates the response identifies the requested parent/sub-issue.

execute_impl itself is now a short, linear sequence of these calls with early returns, matching the original control flow and error messages exactly. No public API signatures changed and no behaviour changed.

Verification

• cargo build — succeeds.
• cargo test --bin ado-aw — all 3322 tests pass (0 failed), including all 9 existing tests for this module (link_github_sub_issue::tests::*), unchanged.
• cargo clippy --all-targets --all-features — clean, no warnings.
• Re-ran the clippy::too_many_lines check scoped to this file — no warning remains (previously 190/100).

Warning

Firewall blocked 1 domain

The following domain was blocked by the firewall during workflow execution:

• spsprodeus21.vssps.visualstudio.com

To allow these domains, add them to the network.allowed list in your workflow frontmatter:

network:
  allowed:
    - defaults
    - "spsprodeus21.vssps.visualstudio.com"

See Network Configuration for more information.

Generated by Cyclomatic Complexity Reducer · auto · 86.3 AIC · ⌖ 10.2 AIC · ⊞ 11.4K · ◷

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