Summer changes preview (PG + RA + #30, combined, do not merge)

[Edwinexd]

Summer changes — combined preview branch

Not for merge — this branch exists to get a single Cloudflare preview environment with all the summer work stacked together. The individual pieces ship via their own PRs (#27, #31, and the Postgres branch).

What's combined here

• Postgres engine (feature/pglite-autocomplete, up to date with master) — dual SQLite/PostgreSQL via PGlite + engine selector, CodeMirror editor, autocomplete, license dialog. Includes the parity fixes (duplicate-column rowMode, NUMERIC/BIGINT normalization, safe engine load with SQLite fallback).
• Relational algebra mode (Add relational algebra mode #27) — RA→SQL transpiler, with π now eliminating duplicate tuples (set semantics; δ stays as an explicit operator).
• Issue Fix 11 B #30 data (Add persons who are neither student nor teacher (#30) #31) — 4 persons who are neither student nor teacher.
• master — German support merged in; RA + engine UI strings relocated into the en/sv/de packs (German machine-translated — needs a native review).

Verified locally

• English DB: Person 25 · neither 4 · both 2
• tsc clean · 249 tests pass · production build green
• All 6 data variants (en/sv/de × sqlite/pg) regenerate with 0 errors

Note for the eventual real merge

Reusing #30's oracle.enc (it's branched off master, which has no Postgres work) breaks 5 PostgreSQL reference queries — YEAR() and boolean = integer — because it lacks the pgQuery overrides. Here the 4 persons were added to the Postgres oracle instead. When #30 and the Postgres work actually merge, the oracle must carry both the new persons and the pgQuery overrides.

[cloudflare-workers-and-pages]

Deploying sql-validator with    Cloudflare Pages

Latest commit:	d658fe0
Status:	✅  Deploy successful!
Preview URL:	https://55f4afd0.dsv-db-sql-validator.pages.dev
Branch Preview URL:	https://preview-summer-changes.dsv-db-sql-validator.pages.dev

View logs

[Edwinexd]

Superseded: #27 (RA), #33 (PostgreSQL), and #31 (neither-persons) are all merged to master as separate merge commits. The oracle carries both the 4 new persons and the pgQuery overrides; all 6 data variants regenerate with 0 errors and reproduce the committed data. Closing this preview branch.