report: migrate Event.Extra to Event.Contexts (sentry-go v0.46+ compat)

[denniszag]

Problem

sentry-go v0.46.0 removed the Extra field from sentry.Event
(getsentry/sentry-go#1274). The merge at report/report.go:369 writes
event.Extra[k] = v and no longer compiles. Because report_api.go in
the root errors package imports the report sub-package, the whole
module fails to typecheck for every downstream consumer once they pick up
sentry-go >= v0.46.0.

Fixes #158.

Change

• report/report.go: replace the Extra merge with Contexts; each
  extra is stored as sentry.Context{"value": v} to match the Context
  schema (map[string]interface{}).
• report/report_test.go, fmttests/datadriven_test.go: read the new
  location in the test printers.

Collateral required to compile against sentry-go v0.46.0

• sentry.Transport gained Close() and FlushWithContext(ctx);
  implemented on the test-only interceptingTransport in both
  report/report_test.go and fmttests/datadriven_test.go.
• sentry.NewEvent() now pre-populates Contexts with default
  device/os/runtime/trace entries (map-shaped, not
  {"value": …}). The fmttests printer now filters to entries that
  carry a "value" sub-key, so Sentry defaults don't leak into
  fixtures. Net fixture diff is zero — same == Extra "<key>"
  output as before.
• go.mod: bump getsentry/sentry-go to v0.46.0.
• go directive raised from 1.23.0 to 1.25.0 because sentry-go
  v0.46.0's own go.mod declares go 1.25.0. The redundant
  toolchain go1.23.8 line is dropped. This is forced by the upstream
  dependency, not a preference; happy to split it out if the maintainers
  prefer a separate "bump Go floor" PR first.
• fmttests/datadriven_test.go: pre-existing non-constant format string
  in a call to issuelink.UnimplementedErrorf(...) was flagged by the
  stricter go vet in the Go 1.25 toolchain and was blocking go test;
  fixed with a "%s" format specifier. Behaviour-preserving.

Verification

• go build ./... — clean.
• go test -race ./... — all packages pass except a pre-existing
  environmental failure in withstack.TestReportableStackTrace that
  asserts stack frame filenames contain /errors/ or /errors@ and so
  fails for any checkout located outside a path with /errors in it
  (same failure reproduces on untouched upstream/master; unrelated to
  this change).
• fmttests/testdata/ — zero diff; the -rewrite pass produced no
  changes thanks to the "value" sub-key filter in the printer.

Alternatives considered

1. Use Scope.SetContext inside ReportError instead of merging into
   the event directly. Cleaner in some ways, but breaks test code that
   reads event.Extra["error types"] after BuildSentryReport — extras
   would never land on the event. Chose direct event.Contexts merge to
   preserve the existing read-after-report pattern.
2. Rename the printed == Extra label to == Context. Rejected to
   keep fixture diffs empty; can be renamed in a follow-up.
3. Split "bump Go floor" into its own PR. Willing to do this if
   preferred — just say the word and I'll rebase.

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[Copilot]

Pull request overview

Updates the Sentry reporting integration to compile with getsentry/sentry-go v0.46.0+ after the removal of sentry.Event.Extra, while keeping test fixtures stable.

Changes:

• Migrate Sentry “extra” payload merging from Event.Extra to Event.Contexts (storing each value under a "value" sub-key).
• Update report printers/tests to read from Event.Contexts and filter out Sentry’s default contexts to avoid fixture churn.
• Bump dependencies (notably sentry-go → v0.46.0) and raise the module go version to 1.25.0; update test transports for new sentry.Transport methods.

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
report/report.go	Switch extra merge target from Event.Extra to Event.Contexts.
report/report_test.go	Read “error types” from Contexts and add new sentry.Transport methods to the test transport.
fmttests/datadriven_test.go	Keep fixtures stable by printing only "value"-wrapped contexts; fix vet issue in UnimplementedErrorf; update test transport interface methods.
go.mod	Upgrade sentry-go, raise go directive to 1.25.0, adjust deps.
go.sum	Dependency checksum updates for the module changes.

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[rez1dent3]

@dhartunian @jeffswenson Hello. Can you help with the release?

[dhartunian]

@rez1dent3 @denniszag is go 1.25 acceptable? Seems like that's what the sentry lib upgrade requires and I'd prefer to stay as low as necessary. I'm going to bump separately on master and then you can rebase.

[dhartunian]

master is bumped. let me know if you run into issues. ping me when this is RFAL. Code changes looked good and I can review and cut a release tomorrow.