feat(#11192): support extension libs in messages

[belwalshubham]

Summary

Adds project-defined extension-libs as synchronous Mustache section helpers for translations and outgoing messages.

This allows configurers to transform message values without adding a new built-in helper to CHT Core, for example:

{{#to_devanagari}}{{patient_id}}{{/to_devanagari}}

Closes #11192.

Architecture

flowchart LR
  Couch[("CouchDB<br/>extension-libs")]
  Loader["Extension-libs loader<br/>decode + atomic registry replacement"]

  Couch --> Loader

  Loader --> Webapp["Webapp cache"]
  Loader --> API["API config cache"]
  Loader --> Sentinel["Sentinel config cache"]
  Loader --> Admin["Admin preview load"]

  Webapp --> Translation["Webapp translations"]
  Webapp --> Report["Report detail messages"]
  API --> Export["Message export rendering"]
  Sentinel --> Transitions["Transitions and scheduled SMS"]
  Admin --> Preview["Message queue preview"]

  Translation --> MessageUtils["message-utils<br/>template(opts) / generate(opts)"]
  Report --> MessageUtils
  Export --> MessageUtils
  Transitions --> MessageUtils
  Preview --> MessageUtils

  MessageUtils --> Output["Consistent rendered message"]

Loading

Changes

• Adds @medic/extension-libs for loading and decoding the extension-libs CouchDB document.
• Refactors message-utils.generate and message-utils.template to accept an options object containing extensionLibs.
• Keeps positional argument compatibility for downstream callers while migrating all CHT Core production call sites.
• Exposes function exports as Mustache section helpers, using the attachment filename without the .js suffix.
• Ensures built-in helpers take precedence over extension-lib name collisions.
• Loads and refreshes extension-libs in API and Sentinel when the document changes.
• Passes extension-libs through transitions, scheduled/due messages, API message exports, Webapp report details and validation messages, and Admin message queue previews.
• Adds a Webapp translation parser that uses extension-lib helpers for Mustache sections while preserving the default parser for normal and compiled MessageFormat translations.
• Treats a missing document as an empty registry, skips malformed attachments, and retains the previous valid registry after transient load failures.

Security

Extension-libs are trusted application configuration uploaded by authorized administrators. This change does not present extension-lib execution as sandboxed.

Verification

Manual end-to-end evidence

The following screenshot records the manually executed live CouchDB flow. It uses a real extension-libs document and attachments, the production @medic/extension-libs loader, and the production message-utils rendering path.

Manual steps verified:

1. Created an isolated cht_11192_e2e database on CouchDB 3.5.2.
2. Uploaded to_devanagari.js as an attachment on the extension-libs document.
3. Loaded the real attachment with the production extension-libs loader.
4. Rendered an outgoing message through message-utils.generate and confirmed ID १२३४५.
5. Replaced the document attachment with uppercase.js.
6. Reloaded the extension-libs registry and confirmed the previous helper was atomically replaced.
7. Rendered through message-utils.template and confirmed Hello ADA.
8. Deleted the isolated test database after verification.

This screenshot is evidence of the loader/reload/rendering end-to-end path. The Admin, API, Sentinel, and Webapp integrations are additionally covered by their regression suites listed below.

• npm run build-dev
• npm run lint
• COUCH_URL=http://medic:password@localhost:5984/medic npm run unit-api — 1,636 passing
• npm run unit-admin — 435 passing
• TZ=UTC COUCH_URL=http://medic:password@localhost:5984/medic npm run unit-sentinel — 231 passing
• npm test --workspace=@medic/extension-libs — 6 passing, 100% coverage
• npm test --workspace=@medic/message-utils — 112 passing, 100% statements/lines
• Webapp Angular compilation and Karma suite command completed successfully.
• Docker-backed API integration suite completed successfully.
• Live CouchDB smoke test:
  • uploaded to_devanagari.js as an attachment;
  • loaded it through the production loader;
  • rendered ID १२३४५ through message-utils.generate;
  • replaced the document with uppercase.js;
  • reloaded it and rendered Hello ADA through message-utils.template;
  • deleted the isolated temporary database afterward.

Notes for reviewers

• The shared loader centralizes identical attachment decoding and error behavior across browser and server runtimes.
• Application services still own their loading/cache lifecycle and explicitly inject the current extension-lib snapshot into message-utils.
• The options-object refactor follows the direction discussed in Support extension-libs in translations and outgoing messages #11192 and avoids adding another positional parameter to the existing APIs.