feat(sub12a): add fp.step.template.input

Operation-measurement definitions for library step templates. The
input_type selection covers Steelhead's input shapes (text, number,
boolean, selection, date, signature, time_hms, time_seconds,
temperature, thickness, pass_fail).

target_min/max + target_unit are structured (not embedded in the name
string the way Steelhead does it) so the traveller report can render
target vs actual side-by-side and colour-code out-of-range values.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating/models/fp_step_template_input.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+# Copyright 2026 Nexa Systems Inc.
+# License OPL-1 (Odoo Proprietary License v1.0)
+# Part of the Fusion Plating product family.
+
+from odoo import fields, models
+
+
+class FpStepTemplateInput(models.Model):
+    """Operation measurement definition on a step library template.
+
+    Recorded *during* a step (e.g. "Actual Time", "Plating Thickness").
+    Distinct from transition_input_ids which fire when leaving the
+    step.
+    """
+    _name = 'fp.step.template.input'
+    _description = 'Fusion Plating — Step Template Input'
+    _order = 'sequence, name'
+
+    name = fields.Char(string='Name', required=True, translate=True)
+    template_id = fields.Many2one(
+        'fp.step.template', string='Template',
+        required=True, ondelete='cascade', index=True,
+    )
+    input_type = fields.Selection([
+        ('text', 'Text'),
+        ('number', 'Number'),
+        ('boolean', 'Yes/No'),
+        ('selection', 'Selection'),
+        ('date', 'Date / Time'),
+        ('signature', 'Signature'),
+        ('time_hms', 'Time (HH:MM:SS)'),
+        ('time_seconds', 'Time (seconds)'),
+        ('temperature', 'Temperature'),
+        ('thickness', 'Thickness'),
+        ('pass_fail', 'Pass / Fail'),
+    ], string='Input Type', required=True, default='text')
+    target_min = fields.Float(string='Target Min')
+    target_max = fields.Float(string='Target Max')
+    target_unit = fields.Char(string='Target Unit',
+        help='Display unit, e.g. "min", "°F", "A", "FT2", "in".')
+    required = fields.Boolean(string='Required', default=False,
+        help='If True, sign-off is hard-blocked while this input is blank.')
+    hint = fields.Char(string='Hint')
+    selection_options = fields.Text(string='Selection Options',
+        help='Comma-separated when input_type is "selection".')
+    sequence = fields.Integer(string='Sequence', default=10)