feat(bal): Group C settings-dialog improvements (editable dates, narrower RAW box, warning/reset/support, tooltips, bold locktime)

C2 - 'Editable dates' option (default OFF):
  - new EDITABLE_DATES config; checkbox in settings dialog
  - WillSettingsWidget.apply_editable_dates() re-locks/unlocks the
    delivery-time and check-alive fields, called from update_all() so the
    toggle takes effect immediately (same mechanism as Hide Invalidated)
  - EDITABLE_DATES included in the Reset-to-defaults list

C3 - RAW date box narrowed to ~1/3 (input box 6 chars); the trailing
  label that shows the computed absolute date kept at 10 chars (fixed a
  truncation regression)

C4 - settings dialog:
  (a) bold red warning at the top
  (b) 'Reset setting' button restoring all 7 dialog settings to defaults
      (single source of truth: BalConfig.default), not touching wills
  (c) bold 'Support: bitcoin-after.life' link (opens via webopen)

C5 - tooltips: calendar 'Export reminder dates to your calendar (.ics)',
  fee field 'Mining fee rate in sat/vByte used for the will transactions',
  fee '丰' icon 'Miner fee, click for more information' (tooltip font scoped
  to QPushButton so it matches the other tooltips)

C6 - Locktime column rendered in bold in the will list

tests/test_group_c_settings.py: 4 new tests (EDITABLE_DATES default/toggle,
  reset restores all dialog settings incl. EDITABLE_DATES, reset leaves
  unrelated config untouched). Full suite: 210 passed.

bal/core/plugin_base.py

@@ -175,6 +175,12 @@ class BalPlugin(BasePlugin):
         # (handled by BalWindow.get_wallet_password). Default ON.
         self.AUTO_SIGN = BalConfig(config, "bal_auto_sign", True)
 
+        # EDITABLE_DATES (Group C / C2): when enabled, the delivery-time and
+        # check-alive date fields are editable everywhere (toolbar / Heirs tab),
+        # not only inside the "Build your will" wizard. Default OFF, so the dates
+        # stay display-only outside the wizard unless the user opts in.
+        self.EDITABLE_DATES = BalConfig(config, "bal_editable_dates", False)
+
         self.NO_WILLEXECUTOR = BalConfig(config, "bal_no_willexecutor", True)
         self.HIDE_REPLACED = BalConfig(config, "bal_hide_replaced", True)
         self.HIDE_INVALIDATED = BalConfig(config, "bal_hide_invalidated", True)