refactor: reduce complexity of resolve_reviewer_identity in create_pull_request.rs

[github-actions]

What was complex

resolve_reviewer_identity in src/safeoutputs/create_pull_request.rs had a cognitive complexity of 18 (threshold: 15). The complexity came from three layers stacked together:

1. Three-condition GUID check inline in the function body (&&-chained boolean expressions)
2. Doubly-nested match — outer on the HTTP send result, inner on JSON parsing
3. Triple &&-let chain inside the success arm to navigate results[0].identities plus a for loop with its own &&-let condition and a separate fallback &&-let

What changed

Two focused helpers extracted:

fn is_reviewer_guid(s: &str) -> bool

Encapsulates the three-condition GUID check (length 36, exactly 4 hyphens, all hex/hyphen chars). Makes the call site read as intent, not implementation.

fn find_identity_in_response(data: &Value, reviewer: &str) -> Option<String>

All Identity Picker JSON navigation in one place:

• Uses ? for early return when fields are missing (replaces the triple &&-let chain)
• Contains the exact-match loop (by display name or mail)
• Falls back to first result when no exact match

async fn resolve_reviewer_identity (simplified)

Now reads as four sequential steps:

1. GUID fast-path → is_reviewer_guid
2. Send HTTP request → early return on error
3. Check status code → early return on non-success
4. Parse JSON → find_identity_in_response; warn if None

Before / After complexity

Function	Before	After
resolve_reviewer_identity	18	< 15 (zero warnings)
find_identity_in_response	— (new)	< 15
is_reviewer_guid	— (new)	< 5

Verification

• cargo build — clean
• cargo test — all tests pass
• cargo clippy --all-targets --all-features — clean (fixed one collapsible-if suggestion in the extracted helper)
• cargo clippy -W clippy::cognitive_complexity with threshold=15 — zero warnings for create_pull_request.rs

Warning

Firewall blocked 2 domains

The following domains were blocked by the firewall during workflow execution:

• spsprodeus21.vssps.visualstudio.com
• spsprodweu4.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"
    - "spsprodweu4.vssps.visualstudio.com"

See Network Configuration for more information.

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