feat(config): add pre-parsed-default overload for register_key_combo (v3.2.4)

[coderabbitai]

Summary

In src/config.cpp, register_press_combo / register_hold_combo pre-parse default_value into current_combos (lines ~998-1004) and then call register_key_combo, which re-parses the same default_value_str. This causes duplicate WARNING logs when the C++ literal default contains a typo (e.g. register_press_combo(..., "ctrl+xyzzy")).

Root cause

register_key_combo synchronously invokes the setter at line 985 with the re-parsed default. Passing "" to avoid the double-parse regresses behavior: the closure immediately clobbers the pre-parsed current_combos with an empty list, so the binding has no keys unless the INI overrides it.

Proposed fix (Option 2 — cleanest)

Add a pre-parsed-default overload on register_key_combo that accepts a KeyComboList directly instead of string_view, so callers that have already parsed the default can skip the re-parse step:

// New overload
bool register_key_combo(
    std::string_view section,
    std::string_view key,
    KeyComboList      parsed_default,   // pre-parsed
    std::string_view  log_key_name,
    std::function<void(KeyComboList)> setter
);

register_press_combo / register_hold_combo would call this overload after their existing parse, eliminating the double-parse and the spurious WARNING.

Alternatives considered

1. Skip-initial-seed flag in the closure — works but adds shared mutable state for a developer-error edge case.
2. Reorder register_press before register_key_combo + skip-seed flag — still needs the flag.

Impact of the current behavior

• Fires only on C++ literal typos in default_value, once at process startup, and only when the INI does not override the key.
• Self-correcting: warning vanishes once the developer fixes the typo.
• User-supplied INI typos go through a single parse path (one WARNING, as documented).

References

• PR feat: combo opt-out sentinels, hot-reload safety, and lifecycle docs #78 (v3.2.3): feat: combo opt-out sentinels, hot-reload safety, and lifecycle docs #78
• Review comment: feat: combo opt-out sentinels, hot-reload safety, and lifecycle docs #78 (comment)
• Requested by: @tkhquang

Target milestone

v3.2.4