docs(claude-apps-gateway): fix geo cross-region inference prefix — au, not apac

[bsnehanshu]

What

Every reference to the apac. geo cross-region inference prefix in claude-apps-gateway
was wrong. Anthropic's models on Bedrock use au. for the Australia/APAC geo profile, not
apac. — there is no apac. prefix. Additionally, jp. exists as a fourth geo prefix for
some models (Opus 4.8, Haiku 4.5) but not others (Sonnet 5 has no jp. profile).

Fixed in:

• CLAUDE.md — the "Bedrock IAM needs two ARN families" constraint note
• README.md — the IAM policy section + the gateway.yaml inline comment
• cdk/README.md — the "Regions & data residency" geo-prefix instructions
• docs/deployment.md — the model-ID resolution troubleshooting note
• cdk/gateway.yaml.template — the model-catalog inline comment
• cdk/gateway.yaml.example — the model-catalog inline comment
• cdk/test/gateway-stack.test.ts — a comment referencing the same (incorrect) prefix list

Also tracks cdk/package-lock.json (generated by npm install for this change), for the
same reason as #265 — reproducible synth/test and Dependabot coverage of transitive deps.

Verification

• Checked the actual Bedrock model cards (model-card-anthropic-claude-opus-4-8.html,
  model-card-anthropic-claude-sonnet-5.html) via the AWS Documentation MCP server —
  Opus 4.8's Geo inference IDs are us., eu., jp., au.anthropic.claude-opus-4-8;
  Sonnet 5's are us., eu., au.anthropic.claude-sonnet-5 (no jp.). No apac. prefix
  exists on either.
• Repo-wide grep -rn "apac\." (no file-type filter) — zero matches, confirmed clean.
  An earlier pass only checked .md/.yml/.ts files and missed the two
  gateway.yaml.template/.example occurrences; this pass is unfiltered.
• python3 -c "import yaml; yaml.safe_load(open('gateway.yaml.example'))" — valid YAML
  (.template is not YAML-parseable as-is — it has @@PLACEHOLDER@@ tokens by design,
  same as before this change; not a regression)
• cd cdk && npm test — 17/17 passed, including the test whose comment changed
• cd cdk && npx cdk synth -c imageReady=false — exit 0, clean synth

Note

Discovered while checking the repo for drift related to the Claude Opus 5 announcement
(this package's docs already reference multiple model generations, so it was a natural
place to check prefix accuracy against the current model lineup). Unrelated to the Opus 5
catalog swap itself (#264) — this bug predates that PR and affects the geo-prefix guidance
for every model in the catalog, not just Opus 5.

[bsnehanshu]

Approved: geo-prefix claim verified against live Bedrock model cards (model-card-anthropic-claude-opus-4-8.html, model-card-anthropic-claude-sonnet-5.html) via AWS Documentation MCP — au. is correct, apac. isn't a real prefix, jp. exists for Opus 4.8/Haiku 4.5 but not Sonnet 5. Repo-wide grep for apac. confirmed clean. CDK tests (17) and synth pass. CI green, no conflicts.

[bsnehanshu]

Sources for the geo-prefix verification above: Claude Opus 4.8 model card and Claude Sonnet 5 model card — Regional Availability section.