fix: Make action attempt error and result nullable

[razor-x]

Problem

SDK audit finding H6 (high): the generated ActionAttempt type collapses the API's per-status variants (21 action types × 3 statuses) and claims non-null error and result on every variant:

const aa = await seam.locks.unlockDoor({device_id}, {waitForActionAttempt: false})
aa.result.was_confirmed_by_device  // typechecks — TypeError at runtime: result is null on pending

SucceededActionAttempt<T> = T & {status:'success'} was an intersection that recovered nothing, and SeamActionAttemptFailedError read actionAttempt.error.message unguarded.

Fix

Root cause is upstream: @seamapi/blueprint's createActionAttempts merges the per-status OpenAPI variants and deliberately keeps the non-nullable error/result definitions — the JS templates already render isNullable correctly. So the fix is a codegen normalization (mirroring seamapi/php#479, which faced the same blueprint limitation and also kept action_type-discriminated variants): mark error and result nullable on every action-attempt variant and append the same doc sentence PHP uses — "Null while the action attempt is pending or when this value does not apply."

Regeneration touches exactly one generated file, src/lib/resources/action-attempt.ts (21 variants × error+result).

Hand-written follow-through in resolve-action-attempt.ts:

• SucceededActionAttempt<T> asserts result: NonNullable<T['result']>; error: null, and FailedActionAttempt<T> the mirror — so (await seam.locks.unlockDoor(...)).result.was_confirmed_by_device keeps compiling and is now actually safe.
• SeamActionAttemptFailedError falls back to 'Action attempt failed' / code 'unknown' for a failed attempt without an error object instead of crashing on a null dereference.

Breaking-change note

Compile-time-only tightening that fixes a type lie — runtime behavior of well-formed responses is unchanged (the API always sent null). Code reading aa.error.x/aa.result.x on an unnarrowed attempt stops compiling, which is the point; narrow via resolveActionAttempt/waitForActionAttempt or a status check. PHP shipped its analog as a feat: in a minor.

Tests

• Type-level assertions: unnarrowed error/result reads are @ts-expect-error; SucceededActionAttempt/FailedActionAttempt narrowing compiles. On reverted source these produce 4 type errors — proving the old types lied.
• Runtime: a failed attempt with error: null rejects with SeamActionAttemptFailedError('Action attempt failed', code 'unknown'); on reverted source this is a bare TypeError: Cannot read properties of null (reading 'message').

Full suite (127 tests), lint, typecheck green. npm run generate diff verified to touch only the expected sites.

Part of applying the rev-3 SDK audit (one PR per finding). Related: #1002–#1006.

🤖 Generated with Claude Code

https://claude.ai/code/session_01B8xeJm2Hd923k8uo6eoFd2

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