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/mod.rs

@@ -163,10 +163,15 @@ pub enum Commands {
     /// Initialize configuration and database
     #[command(after_help = "\x1b[1mExamples:\x1b[0m
   lore init                                                   # Interactive setup
+  lore init --refresh                                         # Register projects from existing config
   lore init --force                                           # Overwrite existing config
   lore --robot init --gitlab-url https://gitlab.com \\
     --token-env-var GITLAB_TOKEN --projects group/repo        # Non-interactive setup")]
     Init {
+        /// Re-read config and register any new projects in the database
+        #[arg(long, conflicts_with = "force")]
+        refresh: bool,
+
         /// Skip overwrite confirmation
         #[arg(short = 'f', long)]
         force: bool,