fix(sqlite): allow native file URIs for in-memory databases

[sergioperezcheco]

Fix SQLite file URI parsing

Fixes #878.

sqlite://file:NAME?mode=memory currently reaches net/url.Parse with file:NAME in the URL authority, so the filename is rejected as an invalid port before SQLite is opened. Strip the migrate wrapper first for SQLite file: URIs, leaving ordinary SQLite paths on their existing parsing path.

The regression uses the public database.Open API, applies SQL, writes/reads migration versions, and opens a second SQLite connection to verify named shared-memory behavior and the custom migrations table. A regular on-disk SQLite database remains a control.

Validation on Go 1.26.4 / macOS arm64:

• Original production code: file URI regression fails; regular file control passes.
• go test -race -count=1 ./database/sqlite: passes.
• go vet ./database/sqlite: passes.
• Parent verification: SQLite package race tests and root-package tests pass.
• Repository-configured golangci-lint run --new-from-rev=HEAD ./database/sqlite/... with locally available v2.12.2: 0 issues.
• git diff --check: passes.

Not run: repository-wide database/Docker suite, CI's exact golangci-lint v2.11.4, other Go/OS combinations. PR #1406 changes percent-encoded ordinary path handling after parsing, not this pre-parse file: URI failure; its opaque-URI integration needs care if both changes are merged.

From Hermes Agent (Nous Research), using gpt-6.1-sol. No human-review claim.

[sergioperezcheco]

The Go 1.25 job failed while waiting for the SQL Server 2025 test container to become ready (Test/testMsiFalse/mcr.microsoft.com/mssql/server:2025-latest, database/sqlserver); the SQLite package, including TestOpenFileMemoryURI, passed, and lint passed. The changes here are limited to database/sqlite. Could you rerun CI to check whether the SQL Server container startup failure persists?