idd-all Phase 0.5: make third-party detection lazy (skip gh api user/probe for explicit always/never)

[kiki830621]

Problem

Surfaced during /idd-verify of #192 (regression lens, LOW — perf). See verify report: #192 (comment)

In idd-all Phase 0.5, the third-party detection (#192) issues gh api user + a dedicated gh repo view --json viewerPermission before the case "$PR_POLICY", in the IS_FORK=false branch. So:

• gh api user fires on every non-fork idd-all invocation (incl. own-repo common path).
• When pr_policy is explicitly always/never, the computed IS_THIRD_PARTY is discarded (those branches don't consult it) — the API calls are wasted.

Unlike idd-issue (which folds viewerPermission into the existing gh repo view), idd-all's fork check only requests isFork, so it pays a separate probe.

Proposed fix

Make third-party detection lazy in idd-all Phase 0.5: compute IS_THIRD_PARTY only inside the absent) case (the only branch that uses it). Optionally fold viewerPermission into the existing fork gh repo view call.

Refs #192.

[kiki830621]

Verify (via PR #198) — PASS

Bundled into the verify follow-up cluster PR #198 (one branch, one verify). 4-lens + Devil's-Advocate, converged PASS (#195 needed one round of fixes to close a split-brain the DA caught). Tests: git-ignore-block 26/26 + stage45 23/23.

Verify-gated — ready to merge. After merge, finalize via /idd-close.

[kiki830621]

Closing Summary

Problem

idd-all Phase 0.5 computed third-party detection (gh api user + gh repo view --json viewerPermission) BEFORE the case "$PR_POLICY", so it ran on every non-fork invocation — even when pr_policy was explicitly always/never (which discard the result) → wasted API round-trips.

Root Cause

Detection was eager; only the absent default branch consults it.

Solution

Move the IS_THIRD_PARTY / SELF_LOGIN computation INTO the absent) case. Explicit pr_policy: always/never (and --pr/--no-pr, handled earlier) now skip the probe entirely.

Verification

2-lens + DA (PR #198): confirmed IS_THIRD_PARTY / SELF_LOGIN are referenced ONLY inside the absent branch (no out-of-scope undefined-variable use); the absent logic is byte-identical to before; ask/always/never paths unaffected.

Changes

PR #198 (squash → 6531b6d). idd-all Phase 0.5.