feat(ci): make api-sync deterministic, drop claude-code-action

[ericviana]

Summary

Replaces the LLM-driven api-sync.yml (Claude via claude-code-action, gated on CLAUDE_CODE_OAUTH_TOKEN) with a pure, reviewable script pipeline in scripts/api-sync/. No LLM, no OAuth token, in the loop at all.

• parse-changelog.ts — parses blindpay-v2's spec-diff.ts markdown into structured events; fails loudly on anything it doesn't recognize instead of dropping it.
• known-resources.ts — the generator's entire "what can I touch" map (path -> resource -> function name). A path not in this map is unmappable by construction.
• classify.ts — splits events into applicable (an additive optional field on the REQUEST body of a known create/update path — the one pattern every historical additive api-sync PR here actually used, e.g. feat: sync CLI with API changes #6) and needsHuman (everything else: removed fields, enum changes, response-only field changes, new/removed endpoints/methods/schemas).
• apply.ts — anchor-based, idempotent source patches to resources.ts, index.ts, and schema.ts for each applicable field.
• version-bump.ts — minor if any endpoint/method/enum value was added or removed, patch otherwise. Scripted, not guessed.
• generate.ts — orchestrates the above and emits a SUMMARY_JSON line the workflow reads.

api-sync.yml now: fetches the changelog, runs the generator, runs this repo's existing ci.yml commands (typecheck/lint/test/build) against the result, commits, opens/updates a PR — and only calls gh pr merge --auto --squash when the generator reports nothing needed a human. If a changelog contains only unmappable changes, no PR is opened (there's no diff); a plain issue is opened instead so it isn't silently lost.

Also flipped the repo's allow_auto_merge setting on via the GitHub API (was off, required for --auto to work), and added scripts/ to bun run typecheck/lint so the generator itself is covered by CI.

Determinism proof

Ran the generator twice from the same changelog fixture against two independent copies of this repo:

1d78dc1c036346952fb260cbfa4309d501c348146b309c051986270132112d0c  repo1/src/commands/resources.ts
bed9aa5611cd5bfcfce5c1fefb070689532686d5f0da7b144b11e8710748f477  repo1/src/index.ts
b7526eb022559f45024f2f90a365dd57ce9552d584ba46cd16707d48e0bb9025  repo1/src/commands/schema.ts
5d79b9016e0d628dc72412f461ab34cacdc6dd3885ba4c1f7982856a99b7a1e0  repo1/package.json
1d78dc1c036346952fb260cbfa4309d501c348146b309c051986270132112d0c  repo2/src/commands/resources.ts
bed9aa5611cd5bfcfce5c1fefb070689532686d5f0da7b144b11e8710748f477  repo2/src/index.ts
b7526eb022559f45024f2f90a365dd57ce9552d584ba46cd16707d48e0bb9025  repo2/src/commands/schema.ts
5d79b9016e0d628dc72412f461ab34cacdc6dd3885ba4c1f7982856a99b7a1e0  repo2/package.json

Byte-identical. Re-applying the generator a second time against already-patched output is also a no-op (see the idempotency tests in scripts/api-sync/__tests__/apply.test.ts).

Equivalence proof

Fetched the real parent commit of historical PR #6 (ba11caa) and its first commit (125c09b, the additive swift_ifsc_branch_code field on createBankAccount). Built a changelog fixture describing that exact spec change and ran the generator against the ba11caa baseline. Diff against the real merged commit:

--- resources.ts (real PR #6)                    --- resources.ts (generator)
+ swiftIfscBranchCode?: string                    + swiftIfscBranchCode?: string   (same anchor)
+ swift_ifsc_branch_code: options.… ?? null,       + if (options.swiftIfscBranchCode !== undefined)
  (inline in the body object literal)                 body.swift_ifsc_branch_code = options.…
                                                        (statement before the apiPost call)

--- index.ts
+ .option('--swift-ifsc-branch-code <code>',       + .option('--swift-ifsc-branch-code <value>',
    'SWIFT/IFSC branch code (international_swift     'Swift Ifsc Branch Code (added by api-sync)')
     accounts)')

Same flag name, same anchor point, functionally equivalent body handling (the generator omits the key entirely instead of sending null when the flag isn't passed — arguably better, and matches the newer partial-update convention already used elsewhere in this file). The only differences are the auto-generated help text (cosmetic; a human can refine it in review) and that the real PR still bumped the old constants.ts-based version scheme, which the very next commit in that same PR replaced with the package.json scheme this generator uses. Both diffs are explained line-by-line, not hidden.

Scope, honestly

The CAN-express surface is intentionally narrow: additive optional fields on the request body of a resource already in known-resources.ts. Field removals, enum-only changes, and response-field changes are routed to needs-human even though earlier LLM-driven syncs sometimes handled them — see the comment block at the top of classify.ts for why each isn't safe to script deterministically today (no stable anchor for enum help text, "is this interesting enough for a column" is a judgment call, removing a flag can break someone's script). New resources/endpoints always need hand-written command wiring and are never touched.

v2-side proposals (not applied — I don't touch blindpay-v2)

1. sdk-sync.yml only pushes changelog.md (markdown) and the OLD baseline spec to downstream SDK repos, not the NEW spec JSON (unlike mcp-sync.yml, which does push full JSON to blindpay-mcp). Pushing the new spec JSON alongside the changelog would let this generator diff structured JSON directly instead of parsing markdown, which is more robust long-term and would let future generators (here or in other SDKs) go beyond the field/enum surface safely.
2. scripts/spec-diff.ts could optionally emit a parallel changelog.json (structured events) alongside the markdown, generated from the same diff pass — removes the need for every downstream repo to hand-roll a markdown parser like parse-changelog.ts here.

Test plan

• bun run typecheck, bun run lint, bun test, bun run build all pass on this branch
• Determinism: two independent runs of the generator on the same input hash-identical (above)
• Equivalence: regenerating PR feat: sync CLI with API changes #6's historical change reproduces it, diff explained line-by-line (above)
• scripts/api-sync/__tests__/ covers the parser (recognized formats + fail-loud on unrecognized ones), the classifier (applicable vs needs-human for every event kind), and apply.ts (real repo source, plus idempotency)
• First live repository_dispatch from blindpay-v2 after merge, to confirm the end-to-end flow against a real changelog