docs(NES-84): add supported-database matrix and first-run setup wizard section

[ericfisherdev]

Summary

Implements NES-84: documents the full set of supported database sources in one place.

What changed

• README → "Supported databases" matrix: an at-a-glance table covering Postgres (local/remote), Supabase (cloud/local CLI), and PocketBase (🚧 planned, linking the NES-82 spike / NES-81), each linking to its setup details.
• README → "First-run setup wizard" section: documents the interactive path (previously undocumented) — provider choice (Postgres/Supabase), Supabase pooler mode + SSL root cert, validate→migrate→persist→restart, and the NESTOVA_SETUP_TOKEN gate (NES-78 + NES-83).
• .env.example: a Database header cross-linking the matrix.

Verification

• Every referenced env var (DB_PROVIDER, DB_POOL_MODE, DB_SSL_ROOT_CERT, MIGRATE_DATABASE_URL, NESTOVA_FORCE_SETUP, NESTOVA_SETUP_TOKEN) confirmed present in the code.
• Internal anchors and the docs/pocketbase-backend-spike.md link resolve.
• Smoke-tested the documented connect+migrate path (cmd/migrate status against a live Postgres → all 17 migrations reported applied).

Docs only — no code changes.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation
  • Added clearer guidance on supported database options, including local/remote Postgres, Supabase, and a planned PocketBase option.
  • Documented first-run setup behavior, connection details, migration flow, and onboarding steps for new installations.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: 6543e5ee-2ea7-4687-b727-94a59d2726eb

📥 Commits

Reviewing files that changed from the base of the PR and between 3adf572 and e65ce74.

📒 Files selected for processing (2)

• .env.example
• README.md

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📝 Walkthrough

Walkthrough

The PR adds README documentation for supported database targets and the first-run setup wizard, and adds a matching database comment block to .env.example.

Changes

Database documentation

Layer / File(s)	Summary
Supported databases README.md, .env.example	Adds a supported-databases matrix for local/remote Postgres, Supabase cloud/local CLI, and planned PocketBase, plus a matching .env.example comment block that points to the README guidance.
First-run setup wizard README.md	Documents wizard activation, the connection and provider inputs it collects, and the submit flow that validates connectivity, runs migrations, persists state, and restarts into onboarding.

Possibly related issues

• NES-84: The supported-database matrix and .env.example cross-link directly match this issue’s documentation goal.
• NES-83: The wizard section documents provider selection and Supabase pooler/SSL options that this issue calls out.
• NES-78: The setup-mode trigger and onboarding handoff expand the first-run database configuration flow described here.
• NES-48: The README and .env.example Supabase references extend the existing Supabase configuration documentation.

Possibly related PRs

• ericfisherdev/nestova#66: Adds Supabase-specific database documentation that the new supported-databases matrix builds on.
• ericfisherdev/nestova#71: Introduces DB_PROVIDER=supabase setup guidance and pooler configuration that the README now documents.
• ericfisherdev/nestova#77: Covers the PocketBase feasibility/design work that the README reflects with a planned PocketBase row.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and accurately summarizes the docs-only database matrix and first-run wizard additions.
Linked Issues check	✅ Passed	The docs cover NES-84, NES-78, and NES-83 requirements, including the supported matrix, wizard flow, provider selection, and .env.example cross-link.
Out of Scope Changes check	✅ Passed	The changes stay within the documented database/onboarding scope and add no unrelated code or features.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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[ericfisherdev]

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