feat(cli): wheels migrate rename-system-tables (F15 Phase 2)

[bpamiri]

Summary

Phase 2 of F15. Phase 1 (#2402) shipped the new `wheels_` defaults plus runtime detection that flips back to `c_o_r_e_` when legacy tables exist. Phase 2 ships the opt-in tooling that actually does the rename when the user is ready.

What's new

Framework

• `Migrator.renameSystemTables(boolean dryRun = false)` — new public method that probes for legacy and new system tables, generates the per-adapter rename SQL, and (unless `dryRun`) executes it inside a transaction. Returns `{success, renamed, skipped, errors, sql}`.

• Per-adapter SQL:

  Adapter	Rename syntax
  MySQL	atomic `RENAME TABLE old1 TO new1, old2 TO new2`
  SQL Server	`EXEC sp_rename` (one per table)
  Oracle	`RENAME old TO new`
  SQLite / PostgreSQL / H2 / CockroachDB	`ALTER TABLE old RENAME TO new`

• Partial-rename safeguard: refuses to run when both `c_o_r_e_` AND `wheels_` versions of a table coexist. The user must drop whichever is empty and re-run — better than silent destruction.

HTTP / CLI

• `/wheels/cli?command=renameSystemTables[&dryRun=true]` — HTTP endpoint that calls the method and returns the result struct as JSON.

• `wheels migrate rename-system-tables [--dry-run]` — new CLI command:

  • default mode: idempotent rename. No-op when legacy tables don't exist. Reports each table renamed.
  • `--dry-run`: prints the per-adapter SQL without executing.

Tests

• Four new specs in `migratorSpec.cfc`:

  • No-op when neither family exists.
  • Happy path: `c_o_r_e_` → `wheels_` rename + settings flip.
  • Refuses on partial state (both exist).
  • `--dry-run` returns SQL without executing.

• Migrator suite: 183 passed (was 179, +4 new)

• Full SQLite suite: 3377 passed, 0 failed (was 3373, +4 new)

Note on FK constraint name

The `fk_core_level` constraint on `wheels_migrator_versions` is NOT renamed by this PR. Constraint names are scoped to their table; renaming them requires DROP/CREATE which is more invasive. Cosmetic blemish only — the constraint still correctly references `wheels_levels.id` because every supported engine auto-updates FK target references on table rename.

Phase 3 (5.0) will drop/recreate the constraint with the new name as part of the final cleanup pass alongside removing all `c_o_r_e_*`-aware code paths.

Usage

# After upgrading to a Wheels version with both Phase 1 and Phase 2:
wheels migrate rename-system-tables --dry-run    # preview
wheels migrate rename-system-tables              # do it

The detection helper from Phase 1 keeps existing apps working without action; this command is purely opt-in.

Test plan

• Migrator suite green locally (183 passed)
• Full SQLite suite green locally (3377 passed)
• CI cross-engine matrix green
• Manual test on a fresh-VM Wheels install: create app, run `wheels migrate latest`, verify `c_o_r_e_` exists, run `wheels migrate rename-system-tables`, verify `wheels_` exists and migrations still work

🤖 Generated with Claude Code