feat: create sqlx.toml format (#3383)

* feat: create `sqlx.toml` format

* feat: add support for ignored_chars config to sqlx_core::migrate

* chore: test ignored_chars with `U+FEFF` (ZWNBSP/BOM)

https://en.wikipedia.org/wiki/Byte_order_mark

* refactor: make `Config` always compiled

simplifies usage while still making parsing optional for less generated code

* refactor: add origin information to `Column`

* feat(macros): implement `type_override` and `column_override` from `sqlx.toml`

* refactor(sqlx.toml): make all keys kebab-case, create `macros.preferred-crates`

* feat: make macros aware of `macros.preferred-crates`

* feat: make `sqlx-cli` aware of `database-url-var`

* feat: teach macros about `migrate.table-name`, `migrations-dir`

* feat: teach macros about `migrate.ignored-chars`

* chore: delete unused source file `sqlx-cli/src/migration.rs`

* feat: teach `sqlx-cli` about `migrate.defaults`

* feat: teach `sqlx-cli` about `migrate.migrations-dir`

* feat: teach `sqlx-cli` about `migrate.table-name`

* feat: introduce `migrate.create-schemas`

* WIP feat: create multi-tenant database example

* fix(postgres): don't fetch `ColumnOrigin` for transparently-prepared statements

* feat: progress on axum-multi-tenant example

* feat(config): better errors for mislabeled fields

* WIP feat: filling out axum-multi-tenant example

* feat: multi-tenant example

No longer Axum-based because filling out the request routes would have distracted from the purpose of the example.

* chore(ci): test multi-tenant example

* fixup after merge

* fix(ci): enable `sqlx-toml` in CLI build for examples

* fix: CI, README for `multi-tenant`

* fix: clippy warnings

* fix: multi-tenant README

* fix: sequential versioning inference for migrations

* fix: migration versioning with explicit overrides

* fix: only warn on ambiguous crates if the invocation relies on it

* fix: remove unused imports

* fix: doctest

* fix: `sqlx mig add` behavior and tests

* fix: restore original type-checking order

* fix: deprecation warning in `tests/postgres/macros.rs`

* feat: create postgres/multi-database example

* fix: examples/postgres/multi-database

* fix: cargo fmt

* chore: add tests for config `migrate.defaults`

* fix: sqlx-cli/tests/add.rs

* feat(cli): add `--config` override to all relevant commands

* chore: run `sqlx mig add` test with `RUST_BACKTRACE=1`

* fix: properly canonicalize config path for `sqlx mig add` test

* fix: get `sqlx mig add` test passing

* fix(cli): test `migrate.ignored-chars`, fix bugs

* feat: create `macros.preferred-crates` example

* fix(examples): use workspace `sqlx`

* fix: examples

* fix(sqlite): unexpected feature flags in `type_checking.rs`

* fix: run `cargo fmt`

* fix: more example fixes

* fix(ci): preferred-crates setup

* fix(examples): enable default-features for workspace `sqlx`

* fix(examples): issues in `preferred-crates`

* chore: adjust error message for missing param type in `query!()`

* doc: mention new `sqlx.toml` configuration

* chore: add `CHANGELOG` entry

Normally I generate these when cutting the release, but I wanted to take time to editorialize this one.

* doc: fix new example titles

* refactor: make `sqlx-toml` feature non-default, improve errors

* refactor: eliminate panics in `Config` read path

* chore: remove unused `axum` dependency from new examples

* fix(config): restore fallback to default config for macros

* chore(config): remove use of `once_cell` (to match `main`)

.github/workflows/examples.yml

@@ -27,7 +27,7 @@ jobs:
           --bin sqlx
           --release
           --no-default-features
-          --features mysql,postgres,sqlite
+          --features mysql,postgres,sqlite,sqlx-toml
 
       - uses: actions/upload-artifact@v4
         with:
@@ -175,6 +175,49 @@ jobs:
           DATABASE_URL: postgres://postgres:password@localhost:5432/mockable-todos
         run: cargo run -p sqlx-example-postgres-mockable-todos
 
+      - name: Multi-Database (Setup)
+        working-directory: examples/postgres/multi-database
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database
+          ACCOUNTS_DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database-accounts
+          PAYMENTS_DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database-payments
+        run: |
+          (cd accounts && sqlx db setup)
+          (cd payments && sqlx db setup)
+          sqlx db setup
+
+      - name: Multi-Database (Run)
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database
+          ACCOUNTS_DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database-accounts
+          PAYMENTS_DATABASE_URL: postgres://postgres:password@localhost:5432/multi-database-payments
+        run: cargo run -p sqlx-example-postgres-multi-database
+
+      - name: Multi-Tenant (Setup)
+        working-directory: examples/postgres/multi-tenant
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/multi-tenant
+        run: |
+          (cd accounts && sqlx db setup)
+          (cd payments && sqlx migrate run)
+          sqlx migrate run
+
+      - name: Multi-Tenant (Run)
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/multi-tenant
+        run: cargo run -p sqlx-example-postgres-multi-tenant
+
+      - name: Preferred-Crates (Setup)
+        working-directory: examples/postgres/preferred-crates
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/preferred-crates
+        run: sqlx db setup
+
+      - name: Multi-Tenant (Run)
+        env:
+          DATABASE_URL: postgres://postgres:password@localhost:5432/preferred-crates
+        run: cargo run -p sqlx-example-postgres-preferred-crates
+
       - name: TODOs (Setup)
         working-directory: examples/postgres/todos
         env: