fix(cdn): honor default locale, locale_strategy, and singleton status in builds

[ABB65]

Problem

A connected project reported published non-i18n content (sponsors) serving 200 {} from the CDN. Root cause was not the reporter's guess — three related bugs in the CDN build path, all from path/meta resolution diverging from MCP's canonical contract.

Fixes

1. Non-i18n meta resolved under supported[0] instead of the default locale

Non-i18n content/meta lives under the default locale (where MCP writes it), which is not necessarily supported[0]. The builder used locales[0], so a project whose default differs from supported[0] (e.g. default=tr, supported=[en,tr]) read a non-existent meta file — the status filter went blind (drafts leaked, meta output empty). Now uses config.locales.default, mirroring brain-cache.ts. Fixed for collections, singletons/dictionaries, and non-i18n documents.

2. resolveContentPath ignored locale_strategy

It only resolved the default file layout. suffix/directory/none i18n models read the wrong path → silent skip in the CDN build and brain cache. Realigned byte-for-byte with MCP's contentFilePath/documentFilePath (all four strategies), preserving Studio's content_path hardening. Document listing under non-file strategies is a documented follow-up (shared with brain-cache's walk).

3. Singleton/dictionary content never status-filtered

Only collection was filtered, so a draft singleton/dictionary published in full. These kinds store meta as a single object; they're now gated as a unit — a non-published unit skips both content and meta so the stale-object sweep GCs any prior copy.

Bonus: narrowed the swallow-everything try/catch

Content-file absence stays a silent skip, but a corrupt meta parse / upload error now surfaces via reportDataLossRisk instead of being swallowed into an unfiltered publish.

Tests

• All four locale_strategy layouts × JSON + document, non-i18n collapse, content_path + strategy, path-traversal/protected rejection.
• Default-locale meta path (reported env), draft singleton hidden, published singleton meta verbatim, legacy no-meta singleton, corrupt-meta surfacing, absent-content silent skip.
• Full unit suite green (743 tests).

Verification note

Confirm on the content repo: meta/sponsors/tr.json says published and meta/sponsors/en.json does not exist → closes the diagnosis 100%.