chore(database): add internal query runtime and projection foundation

[ditadi]

Adds the internal query runtime foundation for the database plugin.

This PR introduces the backend-agnostic DataPath contract, the Drizzle-backed engine adapter, and translation helpers for filters, ordering, relation predicates, includes, and projections.

It also adds default projection handling so private columns are excluded from normal reads, while trusted server code can still request explicit columns when needed.

Later PRs will wire this foundation into the typed entity client, plugin runtime, type generation, CLI, migrations, and deploy flow.

[github-actions]

🔬  Run evals on this PR  ·  Go to Evals Monitor →

[github-actions]

📦 Bundle size report

Compared against bundle-size-baseline.json (main).

@databricks/appkit

npm tarball (packed): 663 KB (+16 B) — gzipped download (dist + bin; excludes release-only docs/NOTICE).

dist	raw	gzip
JS (runtime)	689 KB	241 KB
Type declarations	268 KB	91 KB
Source maps	1.3 MB	448 KB
Other	11 KB	3.7 KB
Total	2.3 MB	784 KB

Per-entry composition (own code — deps external (as shipped))

Entry	Initial (gz)	Lazy (gz)	Total (gz)	node_modules (min)	Own code (min)
.	74 KB	2.5 KB	76 KB	external	244 KB
./beta	39 KB	231 B	39 KB	external	117 KB
./type-generator	19 KB	0 B	19 KB	external	54 KB

Chunks:

Entry	Chunk	Load	Size (gz)
.	index.js	initial	70 KB
.	utils.js	initial	4.0 KB
.	remote-tunnel-manager.js	lazy	2.5 KB
./beta	beta.js	initial	30 KB
./beta	databricks.js	initial	5.7 KB
./beta	service-context.js	initial	3.0 KB
./beta	client-options.js	initial	219 B
./beta	databricks.js	lazy	128 B
./beta	index.js	lazy	103 B
./type-generator	index.js	initial	19 KB

@databricks/appkit-ui

npm tarball (packed): 297 KB — gzipped download (dist + bin; excludes release-only docs/NOTICE).

dist	raw	gzip
JS (runtime)	363 KB	120 KB
Type declarations	203 KB	73 KB
Source maps	672 KB	219 KB
CSS	16 KB	3.3 KB
Total	1.2 MB	415 KB

Per-entry composition (consumer bundle — deps bundled, peerDeps external)

Entry	Initial (gz)	Lazy (gz)	Total (gz)	node_modules (min)	Own code (min)
./js	4.2 KB	49 KB	54 KB	208 KB	11 KB
./js/beta	20 B	0 B	20 B	0 B	0 B
./react	591 KB	49 KB	640 KB	1.8 MB	167 KB
./react/beta	20 B	0 B	20 B	0 B	0 B

Chunks:

Entry	Chunk	Load	Size (gz)
./js	index.js	initial	4.1 KB
./js	chunk	initial	120 B
./js	apache-arrow	lazy	49 KB
./js/beta	beta.js	initial	20 B
./react	index.js	initial	589 KB
./react	tslib	initial	2.1 KB
./react	apache-arrow	lazy	49 KB
./react/beta	beta.js	initial	20 B