feat(init): add --refresh flag for project re-registration

When new projects are added to the config file, `lore sync` doesn't pick
them up because project discovery only happens during `lore init`. 
Previously, users had to use `--force` to overwrite their entire config.

The new `--refresh` flag reads the existing config and updates the
database to match, without modifying the config file itself.

Features:
- Validates GitLab authentication before processing
- Registers new projects from config into the database
- Detects orphan projects (in DB but removed from config)
- Interactive mode: prompts to delete orphans (default: No)
- Robot mode: returns JSON with orphan info, no prompts

Usage:
  lore init --refresh              # Interactive
  lore --robot init --refresh      # JSON output

Improved UX: When running `lore init` with an existing config and no
flags, the error message now suggests using `--refresh` to register
new projects or `--force` to overwrite the config file.

Implementation:
- Added RefreshOptions and RefreshResult types to init module
- Added run_init_refresh() for core refresh logic
- Added delete_orphan_projects() helper for orphan cleanup
- Added handle_init_refresh() in main.rs for CLI handling
- Added JSON output types for robot mode
- Registered --refresh in autocorrect.rs command flags registry
- --refresh conflicts with --force (mutually exclusive)

src/cli/autocorrect.rs

@@ -232,6 +232,7 @@ const COMMAND_FLAGS: &[(&str, &[&str])] = &[
     (
         "init",
         &[
+            "--refresh",
             "--force",
             "--non-interactive",
             "--gitlab-url",