**Steps to reproduce:**
* Install `l10n_mx` module.
* Go to Accounting > Assets and create a new asset.
* Attempt to select a Fixed Asset account in the corresponding field.

**Observed behavior:**
* No existing Fixed Asset accounts correctly show up in the selection.
* Even if an asset goes through by force-creating an account, the automatic depreciation flow fails because the depreciation models generate a single yearly entry instead of monthly, and the depreciation/expense accounts have incorrect account types.

**Cause:**
* The chart of accounts had Accumulated Depreciation template accounts (e.g., `171.05.01`) set to `expense_depreciation` instead of `asset_non_current`, rendering them unavailable for the Accumulated Depreciation field.
* The Depreciation Expense accounts (e.g., `613.05.01`) were conversely set as `expense_direct_cost` instead of `expense_depreciation`.
* The main Fixed Asset accounts (e.g., `156.01.01`) were completely missing the explicit mappings for `asset_depreciation_account_id` and `asset_expense_account_id` within the CSV definition.
* The depreciation models in `account.depreciation.model-mx.csv` were configured with a `method_period` of `12`, resulting in yearly rather than standard monthly entries.

**Fix:**
* Modify `account.account-mx.csv` to convert all `171.xx/183.xx` accounts to `asset_non_current` and all `613.xx/614.xx` accounts to `expense_depreciation`.
* Introduce the `asset_depreciation_account_id` and `asset_expense_account_id` columns into the `account.account-mx.csv` file, properly linking each Fixed Asset account to its correct depreciation targets.
* Update `account.depreciation.model-mx.csv` to use a `method_period` of `1` (monthly) and convert the `method_number` logic from yearly durations to full month durations (12, 36, 60, and 120 months respectively) for creating accurately timed entries.

opw-6091214