refactor: reduce complexity of execute_impl in create_pull_request.rs

[github-actions]

Summary

Refactors CreatePrResult::execute_impl in src/safe_outputs/create_pull_request.rs, which clippy flagged as the most complex function in the codebase (clippy::too_many_lines).

Before / After

• Before: 582 lines (clippy too_many_lines warning threshold is 100)
• After: 237 lines

Approach

Extracted the monolithic function body into focused, well-named helper methods on CreatePrResult:

• build_effective_title — apply title prefix + validate the ADO 400-char title limit
• resolve_repo_alias_and_id — repository alias/ID resolution
• read_and_verify_patch — patch existence, size limit, SHA-256 integrity check
• validate_patch_content — path validation, protected-files check, max-files check
• setup_worktree_and_collect_changes — git worktree creation, branch checkout, patch application, change collection
• resolve_base_commit — recorded base commit or ADO refs API lookup
• ensure_unique_source_branch — retry-with-suffix loop for branch name collisions
• build_pr_description — PR body assembly (stats + symlink notice + footer)
• build_fallback_failure_result — fallback branch-recorded failure result

Also added two small grouping structs, AdoConnection and WorktreeChanges, following the existing PushBranchParams/PrContext convention already used elsewhere in this file to avoid clippy::too_many_arguments.

execute_impl itself is now a short orchestration function that calls these helpers in sequence.

Behavior

No public API or observable behavior changes — this is a pure refactor.

Verification

• cargo build — clean
• cargo test (full workspace suite, including all 58 create_pull_request tests) — all pass
• cargo clippy --all-targets --all-features — clean, no new warnings
• Re-ran clippy::too_many_lines scoped to the file: execute_impl dropped from 582/100 to 237/100

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Generated by Cyclomatic Complexity Reducer · auto · 186.3 AIC · ⌖ 15.8 AIC · ⊞ 11.4K · ◷

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