Add env-gated control for Google Sheets vocab writes (default-on)

[Copilot]

Task 006 still had one open item: allow reading without writing vocabulary rows to Google Sheets. This PR adds an environment-controlled save gate with default-on behavior and updates task/docs to reflect completion.

• Save gating (client + server)

  • Added env-driven gating for vocab persistence:
    • NEXT_PUBLIC_VOCAB_SAVING_ENABLED controls client-side save calls.
    • VOCAB_SAVING_ENABLED provides server-side runtime override for POST /api/vocab.
  • POST /api/vocab now short-circuits with { ok: true, skipped: 'disabled' } when saving is disabled.

• Shared flag parsing

  • Introduced vocabSavingFlag.ts to centralize env parsing and falsey values (0 | false | no | off) and avoid duplicated logic.

• Config + docs

  • Restored and tracked .env.local.example with auth vars plus save-toggle vars.
  • Updated README with build-time vs runtime behavior for the two flags.
  • Marked task 006 as in-review and checked off the pending env-toggle step in project tracking.

// src/modules/vocab-store/vocabSavingFlag.ts
export const isClientVocabSavingEnabled = (): boolean =>
  isEnabled(process.env.NEXT_PUBLIC_VOCAB_SAVING_ENABLED);

export const isServerVocabSavingEnabled = (): boolean =>
  isEnabled(process.env.VOCAB_SAVING_ENABLED ?? process.env.NEXT_PUBLIC_VOCAB_SAVING_ENABLED);

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Project	Deployment	Actions	Updated (UTC)
finnish-learner	Ready	Preview, Comment	Jun 14, 2026 7:33am

[Copilot]

Pull request overview

Adds environment-controlled gating for vocabulary persistence to Google Sheets so the app can be used in “read-only” mode without writing new vocab rows, while keeping default-on behavior.

Changes:

• Introduces shared env parsing for save enablement (NEXT_PUBLIC_VOCAB_SAVING_ENABLED, optional server override VOCAB_SAVING_ENABLED).
• Skips client save calls and short-circuits the server POST /api/vocab when saving is disabled.
• Updates docs/tracking files and restores a committed .env.local.example.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/modules/vocab-store/vocabSavingFlag.ts	Centralized default-on env flag parsing for client/server save gating.
src/modules/vocab-store/saveVocab.ts	Client-side early return when vocab saving is disabled.
src/app/api/vocab/route.ts	Server-side POST early return when saving is disabled.
README.md	Documents the two env flags and clarifies build-time vs server override usage.
.project/tasks/task-006_google-sheets-adapter.md	Marks task status/step completion and logs the save-toggle implementation.
.project/overview.md	Updates task-006 status to in-review in project overview.
.gitignore	Un-ignores .env.local.example so it can be committed.
.env.local.example	Adds example env file including auth vars and save-toggle vars.

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