XCResultToolClient and new-format schema structs (#391) - #441

…t typing (#391, Tasks 8–10) (#447)

* test: pin extension-based attachment typing and map public.data on the legacy backend

Task 10 of the migration plan. The AttachmentType(filenameExtension:)
initializer itself landed with #443; what was missing is the cross-backend
agreement pin and one table entry: LegacyResultReader's UTI fallback omitted
public.data, so an extensionless public.data attachment degraded
.data -> .unknown on the legacy backend only.

Co-Authored-By: Claude Fable 5 <[email protected]>

* fix: surface XCResultToolError diagnoses through LocalizedError

Carried forward from the #441 review: consumers now exist (faults and
warnings format these errors), and localizedDescription printed the generic
NSError boilerplate rather than the command, exit status, and stderr.

Co-Authored-By: Claude Fable 5 <[email protected]>

* feat: export attachments through the modern xcresulttool path

Task 9 of the migration plan. One `export attachments` call per bundle plus
the manifest.json join (activity attachment uuid <-> basename of
exportedFileName) replaces the legacy per-payload export and its lock table;
only the one-shot export is guarded. Run logs come from `get log --type
action` and render from the structured messages, since the new format has
no emittedOutput.

Committed ahead of Task 8 so each commit builds: the reader's payloadStore
property references this type.

Co-Authored-By: Claude Fable 5 <[email protected]>

* feat: add ModernResultReader for the new xcresulttool format

Task 8 of the migration plan. Parity rules carried exactly: statuses map
into the neutral enum (Expected Failure still flattens to unknown
downstream); multi-repetition status derives from the Repetition children
and ignores the parent Test Case's own result (RetryResults reports Passed
there for a Failed-then-Passed test); the tree renders flat, without the
legacy wrapper groups.

Failure text joins the two documents rather than choosing one: measured on
Xcode 26.2, every assertion failure appears both as a failure-flagged
activity row (positioned and timestamped, but stripped of file:line) and as
a Failure Message node (file:line kept, no timestamp). Each message retitles
the first unclaimed failure activity whose title is its exact suffix, in
document order, nested rows included; unmatched messages (skip reasons,
expected-failure notes) append. The plan's original guard kept the activity
title instead, which shipped strictly less information than the spec's
failureTitlePrefix entry documents — coordinator-approved correction,
amended in the plan.

A failed activities query records the new .missingActivities fault; fields
the format structurally lacks never fault, pinned by a full modern-path
render of all three fixtures asserting zero faults.

The sample app gains a parameterized @test so Arguments nodes stop being
fixture-unexercised; its argument sets merge into one rendered row, moving
the TestResults header total from 17 to 18.

Co-Authored-By: Claude Fable 5 <[email protected]>

* docs: amend plan and spec for Tasks 8-10 as executed

The load-bearing correction: failure text is a join of the two documents,
not a choice between them. Measured on Xcode 26.2, the activities document
carries every assertion failure as a positioned, timestamped, sometimes
nested failure row missing only the file:line prefix; the plan's original
anti-double-count guard would have dropped the prefixed Failure Message and
shipped less than the spec's failureTitlePrefix entry documents.
Coordinator-approved retitle-join recorded in both documents.

Mechanical notes: Task 9 commits before Task 8 (type dependency), TestRun is
nested in TestActivities, the AttachmentType initializer shipped failable in
443, and regenerating fixtures after the sample-app change collapses the
plan's 6-of-7 intermediate state.

Co-Authored-By: Claude Fable 5 <[email protected]>

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Co-authored-by: Claude Fable 5 <[email protected]>