fix: Deprecate the ldai module ahead of its move to go-server-sdk-ai

[jsonbailey]

Summary

The ldai module now lives in its own repository, launchdarkly/go-server-sdk-ai, released as v0.10.0. This is the final release of ldai from this repository. The code itself is removed in a follow-up PR.

Two changes:

1. Revert bd4ce7a1 (feat(ldai): stamp modelKey and modelVersion on AI usage events, feat(ldai): stamp modelKey and modelVersion on AI usage events (AIC-2850) #414). That change was never released from this repo, and it already exists in the new repo as feat(ldai): stamp modelKey and modelVersion on AI usage events (AIC-2850) go-server-sdk-ai#17. Leaving it here makes release-please publish ldai/v0.10.0 from this repository, which collides with the version lineage — the new repo continues from 0.9.x, so 0.10.0 must come from there.

2. Mark the module deprecated in ldai/go.mod:

   // Deprecated: this module has moved to github.com/launchdarkly/go-server-sdk-ai.
   module github.com/launchdarkly/go-server-sdk/ldai
   

   This is what surfaces the move in go list -m -u all and on pkg.go.dev. A README only reaches people who open the repo.

Release notes

This PR forces the release to 0.9.4 via the footer below. Without it, release-please still sees the original feat commit in the range since ldai/v0.9.3 and would propose 0.10.0, which is the number the new repo has already used.

The existing open release PR #424 (chore(v7): release ldai 0.10.0) should retitle itself to 0.9.4 once this merges. Worth confirming rather than assuming.

The older ldai versions are not retracted. Retraction would tell Go there is no usable version and can break @latest resolution for anyone still pinned. Deprecation is the right mechanism. All ldai/v* tags stay in place.

Test plan

• go build ./... in ldai/
• go test ./... in ldai/ — all packages pass

Requirements

• I have followed the repository's pull request submission guidelines

Related issues

• AIC-3306

Release-As: 0.9.4

---

Note

Overview
Prepares the in-repo ldai package for its final release before the module lives only at github.com/launchdarkly/go-server-sdk-ai.

go.mod now carries a deprecation comment so go list and pkg.go.dev steer consumers to the new module path.

The unreleased modelKey / modelVersion work is rolled back: those fields are removed from datamodel.Meta, config evaluation no longer reads them from _ldMeta, and Tracker metric payloads no longer include them (including resumption-token reconstruction). newTracker signatures are simplified accordingly, and tests that asserted those event fields are dropped or updated.

This keeps the 0.10.0 version line on the new repository instead of publishing a conflicting ldai/v0.10.0 from this repo (intended release 0.9.4 per PR footer).

^{Reviewed by Cursor Bugbot for commit 3577c5e. Bugbot is set up for automated code reviews on this repo. Configure here.}