feat: introduce oliphaunt

[f0rr0]

Summary

This PR turns the repository into the Oliphaunt product platform: a src/-first polyglot monorepo with native liboliphaunt, first-class WASIX, peer SDKs, Fumadocs documentation, Moon-driven checks/affectedness, release-please metadata, exact-extension inputs, and product-owned CI/release tooling.

The repo migration and product direction are presented as one coherent architecture change.

Product Direction

• Adds native liboliphaunt as the PostgreSQL 18.4 C ABI/runtime boundary.
• Treats Rust, Swift, Kotlin, React Native, TypeScript, and WASIX Rust as peer installable products instead of making Rust or WASM the implicit center.
• Keeps WASIX first-class under src/runtimes/liboliphaunt/wasix plus src/bindings/wasix-rust.
• Models PostgreSQL source, third-party source pins, shared fixtures/contracts, and exact SQL extensions as source inputs in the Moon graph.
• Uses exact extension selection only: no packs, aliases, grouped selectors, or implicit extension leakage into consumer apps.
• Keeps release decisions in standard release-please manifest/config, with product-local release.toml and target metadata for artifact/package facts.

Major Changes

• Reorganizes source into src/runtimes, src/sdks, src/bindings, src/extensions, src/postgres, src/sources, src/shared, and src/docs.
• Removes active PGlite identity, root WASM-only layout, root assets/, root fixtures/, root scripts/, and retired release-plz/custom release graph surfaces.
• Adds Moon projects/tasks for products, runtimes, bindings, source inputs, docs, benchmarks, shared contracts, shared fixtures, and tooling.
• Adds release-please config plus release/package metadata for public products and runtime artifacts.
• Adds exact-extension catalog, generated SDK/mobile/WASIX metadata, extension evidence, PostGIS/PGXS recipes, and policy checks to prevent unselected extension leakage.
• Adds shared JS core for TypeScript/RN protocol/query code and product-specific SDK checks for Rust, Swift, Kotlin, React Native, TypeScript, and WASIX Rust.
• Adds Fumadocs docs product under src/docs, with public docs centralized there and maintainer/internal docs kept under root docs/.
• Adds CI composite setup actions, stable Checks / ... jobs, Moon affected planning, native/WASIX runtime target jobs, split mobile build/E2E jobs, coverage summary, and release-readiness gates.
• Adds benchmark/test structure for native, WASIX, mobile, reports, and promoted baselines while keeping generated measurement output under target/.

Validation

• bun tools/policy/assertions/assert-ci-workflows.mjs
• tools/policy/check-workflows.sh
• tools/policy/check-tooling-stack.sh
• MOON_BIN=/home/sid/.proto/bin/moon /home/sid/.proto/bin/moon run repo:ci-policy
• MOON_BIN=/home/sid/.proto/bin/moon tools/release/release.py check
• MOON_BIN=/home/sid/.proto/bin/moon tools/graph/graph.py check
• .github/scripts/check-release-intent.sh 'feat: introduce oliphaunt' origin/main HEAD f0rr0/extension-release-hardening
• git diff --check