docs: the SDK, and an SDK tab on every reference page

[joaopcm]

Documentation for @propgate/sdk, and the third tab everywhere the docs already showed a call two ways.

A new SDK section

Six pages, mirroring how the CLI section is split:

/sdk	Install, construct, the { data, error, meta } envelope, configuration, the keyless calls, types, and what is covered
/sdk/errors	The PropgateErrorCode table, what gets retried and what deliberately does not, and the rate limits you have to schedule around
/sdk/profiles	Versions, requiredPerDomain, typed requirements
/sdk/domains	The lifecycle, listAll, and a reconciliation loop worth copying
/sdk/webhooks	Endpoints, secret rotation, the delivery ledger, and verifying signatures with @propgate/webhooks rather than this package
/sdk/accounts	Keys and members, and why signup is not here

An SDK tab beside cURL and CLI

All 21 endpoint pages, plus the quickstart, /authentication and the landing page. Thirteen of those pages showed a bare cURL block; those became tabs. The two signup pages keep the pair they had — the flow ends in a mailbox and a server-side client is on the wrong side of it, which both pages already say.

What is guarded, and what is not

Prose stays a person's job. src/lib/sdk.spec.ts takes the rest, in the shape cli.spec.ts established:

• No invented methods. Every propgate.x.y( across the SDK and API pages is checked against a real client, found by reflection rather than a hand-kept list. Verified it bites by renaming one.
• No undocumented methods. Every method the client exposes has to appear somewhere under /sdk.
• No page left behind. Every endpoint page that has an SDK equivalent must show an SDK tab, and the exclusion list is itself checked against the pages that exist, so a stale exclusion cannot quietly drop a page.
• No unexplained error code. The table on /sdk/errors is asserted to name every member of the union.

That last one needed the union to exist at runtime, so PROPGATE_ERROR_CODES is now exported and PropgateErrorCode derives from it — the same shape CHECK_KINDS and WEBHOOK_EVENTS already use here. Changeset included; it is additive.

coverage.spec.ts also learned the new sidebar section, which is what keeps an empty one from silently vanishing.

Checks

pnpm lint, pnpm check, pnpm test (202 docs specs) and next build all pass — 132 static pages, the six new ones included. Spot-checked the built HTML: three tabs on /api/domains/register, Shiki highlighting on the TypeScript panels.

Greptile Summary

The PR adds comprehensive @propgate/sdk documentation and SDK examples throughout the API reference.

• Adds six SDK guide pages covering construction, errors, profiles, domains, webhooks, and accounts.
• Adds SDK tabs to endpoint, authentication, quickstart, and landing-page examples.
• Exports runtime error-code and retry-wait constants and adds documentation coverage checks.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
apps/docs/src/app/(docs)/sdk/webhooks/_snippets.ts	The webhook example now rejects requests outside the exported 300-second tolerance before verifying their signature, resolving the prior replay-window finding.
apps/docs/src/app/(docs)/sdk/errors/page.mdx	The retry documentation now correctly states the conservative 100-second default upper bound and explains the 90.75-second practical ceiling.
apps/docs/src/lib/sdk.spec.ts	Adds automated checks for documented SDK methods, endpoint-tab coverage, error-code coverage, webhook freshness guidance, and retry-duration values.
packages/sdk/src/error.ts	Introduces a runtime error-code tuple and derives the public error-code union from it.
packages/sdk/src/http.ts	Exports the retry-wait ceiling and aligns its duration commentary with the actual three-attempt retry loop.

_{Reviews (2): Last reviewed commit: "fix(docs): check the timestamp in the we..." | Re-trigger Greptile}