Show the API-spec diff summary inline in the PR comment

[turegjorup]

Supersedes #50. Instead of disabling the oasdiff.com upload, keep it — but stop making reviewers click through to see the diff.

Changes

• Both oasdiff steps: keep review: true (upload + review_url output) and set github-token: "" to suppress the action's own standalone link-only comment.
• The workflow's existing sticky comment now renders the changelog inline in a collapsed <details> and appends a 🔍 View the full side-by-side review link (from steps.{breaking,changelog}.outputs.review_url).

Net result per PR (Codecov-style, one comment):

• Non-breaking → ⚠️ headline + collapsed API changes summary + review link.
• Breaking → 🛑 headline + collapsed summary + review link.
• No changes → ✅ resolved (no link; the action returns an empty review_url when there's nothing to review).

Why

oasdiff-action v0.1.5 (#49) posts a link-only comment by default, so the actual diff lived only on oasdiff.com. This keeps the hosted side-by-side review available but surfaces the summary directly on the PR, so you don't have to leave GitHub for the common case. The upload behaviour is unchanged (the spec is public); only where the diff is shown changes.

Note: the API-spec workflow is path-filtered to spec-affecting paths, so the new comment first renders on the next PR that changes src/config/spec (e.g. #46 once it picks this up).

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.99%. Comparing base (191e1ed) to head (9da1a20).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@ Coverage Diff @@## develop #51 +/- ##
==========================================
Coverage 72.99% 72.99% Complexity 232 232 ==========================================
Files 29 29 Lines 648 648 ==========================================
Hits 473 473 Misses 175 175 

Flag	Coverage Δ
unittests	72.99% <ø> (ø)

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