refactor!: demote chime-validation-max-retries to private defvar

This is an internal startup-timing parameter, not a knob real users have
reason to tune through `M-x customize'. I demoted it from defcustom to
defvar and renamed it to `chime--validation-max-retries' to make the
private status explicit. Anyone who was overriding it can keep doing so
with `setq' (the variable still exists, just under the new name).

The three customize-time validation tests went away with the defcustom —
nothing left to validate at customize-time once it stops being a
customize-target. The setter helper still applies to the other five
numeric defcustoms.

Test files that referenced the variable (`test-chime-validation-retry.el',
`test-integration-chime-mode.el') were renamed mechanically along with
the source.

Breaking change: `(setq chime-validation-max-retries N)' becomes
`(setq chime--validation-max-retries N)' if you actually had it. Most
users won't have touched it.

0 files changed, 0 insertions, 0 deletions