Add unified process_newly_available_git_data function

Implement the unified function that handles all post-git-data-available
processing, regardless of how data arrived (git push or purgatory sync).

This function:
- Discovers satisfiable events from purgatory (state and PR events)
- Syncs OIDs to authorized owner repos
- Aligns refs and sets HEAD
- Saves events to database
- Notifies WebSocket subscribers
- Removes from purgatory

New additions:
- ProcessResult struct for tracking processing outcomes
- process_newly_available_git_data async function in src/git/sync.rs
- Helper functions: extract_identifier_from_repo_path, extract_identifier_from_pr_event
- Purgatory::find_prs_for_identifier method for PR event discovery
- Unit tests for all helper functions

Also fixes:
- Simplified extract_domain to avoid url crate dependency
- Removed unused imports in sync/loop.rs

1 files changed, 27 insertions, 0 deletions

diff --git a/src/purgatory/mod.rs b/src/purgatory/mod.rs
index fcb812b..11fe41f 100644
--- a/src/purgatory/mod.rs
+++ b/src/purgatory/mod.rs
@@ -365,6 +365,33 @@ impl Purgatory {
         })
     }
 
+    /// Find all PR events for a specific repository identifier.
+    ///
+    /// PR events reference repositories via `a` tags with format `30617:<owner_pubkey>:<identifier>`.
+    /// This function scans all PR entries and returns those that reference the given identifier.
+    ///
+    /// Note: This is a linear scan since PR events are indexed by event_id, not by identifier.
+    /// For repositories with many PR events, this could be optimized with a secondary index.
+    ///
+    /// # Arguments
+    /// * `identifier` - The repository identifier to search for
+    ///
+    /// # Returns
+    /// Vector of PR purgatory entries that reference this identifier
+    pub fn find_prs_for_identifier(&self, identifier: &str) -> Vec<PrPurgatoryEntry> {
+        self.pr_events
+            .iter()
+            .filter(|entry| {
+                if let Some(ref event) = entry.value().event {
+                    Self::event_references_identifier(event, identifier)
+                } else {
+                    false
+                }
+            })
+            .map(|entry| entry.value().clone())
+            .collect()
+    }
+
     /// Remove a state event from purgatory.
     ///
     /// Removes all entries for the given identifier.