Feature/Fix: Integrate lineage discovery and shadow accounting

Sources/CodexBarCore/Generated/CodexParserHash.generated.swift

@@ -1,5 +1,5 @@
 // Generated by Scripts/regenerate-codex-parser-hash.sh. Do not edit by hand.
 
 enum CodexParserHash {
-    static let value = "cdef6eb9658a43e2"
+    static let value = "a22a4756d8f471d4"
 }

Sources/CodexBarCore/Providers/Codex/CodexLineageDiscovery.swift

@@ -0,0 +1,126 @@
+import Foundation
+
+/// Expands an already bounded rollout-file selection with only the ancestors its documents reference.
+enum CodexLineageDiscovery {
+    struct Report: Equatable, Sendable {
+        let documents: [CodexLineageLedger.Document]
+        let referencedParentDocumentCount: Int
+        let unresolvedParentIDs: Set<String>
+    }
+
+    static func discover(
+        includedFiles: [URL],
+        roots: [URL],
+        checkCancellation: CostUsageScanner.CancellationCheck? = nil) throws -> Report
+    {
+        var locator = ParentFileLocator(roots: roots, checkCancellation: checkCancellation)
+        var documents: [CodexLineageLedger.Document] = []
+        var knownIDs: Set<String> = []
+        var seenPaths: Set<String> = []
+        var pendingParentIDs: [String] = []
+        var unresolvedParentIDs: Set<String> = []
+        var referencedParentDocumentCount = 0
+
+        func remember(_ document: CodexLineageLedger.Document) {
+            documents.append(document)
+            knownIDs.insert(Self.canonicalSessionID(document.ownerID))
+            if let parentSessionID = Self.nonEmpty(document.parentSessionID) {
+                pendingParentIDs.append(Self.canonicalSessionID(parentSessionID))
+            }
+        }
+
+        for fileURL in includedFiles.sorted(by: { $0.path < $1.path }) {
+            try checkCancellation?()
+            let path = fileURL.standardizedFileURL.path
+            guard seenPaths.insert(path).inserted else { continue }
+            try remember(CostUsageScanner.parseCodexLineageDocument(
+                fileURL: fileURL,
+                checkCancellation: checkCancellation))
+        }
+
+        var nextParent = 0
+        while nextParent < pendingParentIDs.count {
+            try checkCancellation?()
+            let parentID = pendingParentIDs[nextParent]
+            nextParent += 1
+            guard !knownIDs.contains(parentID), !unresolvedParentIDs.contains(parentID) else { continue }
+            guard let parentURL = try locator.fileURL(for: parentID) else {
+                unresolvedParentIDs.insert(parentID)
+                continue
+            }
+            let path = parentURL.standardizedFileURL.path
+            guard seenPaths.insert(path).inserted else {
+                unresolvedParentIDs.insert(parentID)
+                continue
+            }
+            let parent = try CostUsageScanner.parseCodexLineageDocument(
+                fileURL: parentURL,
+                checkCancellation: checkCancellation)
+            let ownerID = Self.canonicalSessionID(parent.ownerID)
+            guard ownerID == parentID else {
+                unresolvedParentIDs.insert(parentID)
+                continue
+            }
+            referencedParentDocumentCount += 1
+            remember(parent)
+        }
+
+        return Report(
+            documents: documents,
+            referencedParentDocumentCount: referencedParentDocumentCount,
+            unresolvedParentIDs: unresolvedParentIDs)
+    }
+
+    private static func nonEmpty(_ value: String?) -> String? {
+        guard let value, !value.isEmpty else { return nil }
+        return value
+    }
+
+    private static func canonicalSessionID(_ value: String) -> String {
+        UUID(uuidString: value)?.uuidString.lowercased() ?? value
+    }
+
+    private struct ParentFileLocator {
+        let roots: [URL]
+        let checkCancellation: CostUsageScanner.CancellationCheck?
+        var didIndexRoots = false
+        var filesByID: [String: URL] = [:]
+
+        mutating func fileURL(for sessionID: String) throws -> URL? {
+            let canonicalID = CodexLineageDiscovery.canonicalSessionID(sessionID)
+            if let known = self.filesByID[canonicalID] {
+                return known
+            }
+            if !self.didIndexRoots {
+                try self.indexRoots()
+            }
+            return self.filesByID[canonicalID]
+        }
+
+        private mutating func indexRoots() throws {
+            self.didIndexRoots = true
+            var files: [URL] = []
+            for root in self.roots {
+                try self.checkCancellation?()
+                guard let enumerator = FileManager.default.enumerator(
+                    at: root,
+                    includingPropertiesForKeys: [.isRegularFileKey],
+                    options: [.skipsHiddenFiles, .skipsPackageDescendants])
+                else { continue }
+                while let fileURL = enumerator.nextObject() as? URL {
+                    try self.checkCancellation?()
+                    guard fileURL.pathExtension.lowercased() == "jsonl" else { continue }
+                    files.append(fileURL)
+                }
+            }
+
+            for fileURL in files.sorted(by: { $0.path < $1.path }) {
+                try self.checkCancellation?()
+                if let ownerID = CostUsageScanner.codexRolloutOwnerID(fileURL: fileURL) {
+                    let canonicalID = CodexLineageDiscovery.canonicalSessionID(ownerID)
+                    self.filesByID[canonicalID] = self.filesByID[canonicalID] ?? fileURL
+                }
+            }
+        }
+    }
+}