feat: add import resolution with Xenia-style thunk stubs (M8)

- resolve_imports() rewrites PE import records in-place:
  - Variable slots: 0xD000BEEF | (ordinal & 0xFFF) << 16
  - Thunk stubs: li r3, 0 / li r4, <ordinal> / mtspr CTR, r11 / bctr
- New -r/--resolve-imports flag on the extract command
- Without the flag, extraction is unchanged (byte-for-byte identical)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/imports.rs

@@ -109,6 +109,118 @@ pub fn decode_import_records(pe_image: &[u8], xex: &Xex2File) -> Result<Vec<Reso
     Ok(resolved)
 }
 
+/// Summary of import resolution results.
+#[derive(Debug)]
+pub struct ImportResolutionSummary {
+    /// Total number of import records processed.
+    pub total: usize,
+    /// Number of variable slots written.
+    pub variables_written: usize,
+    /// Number of thunk stubs written.
+    pub thunks_written: usize,
+    /// Per-library breakdown: (library_name, count).
+    pub per_library: Vec<(String, usize)>,
+}
+
+impl fmt::Display for ImportResolutionSummary {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "Resolved {} imports ({} variables, {} thunks)",
+            self.total, self.variables_written, self.thunks_written
+        )?;
+        for (lib, count) in &self.per_library {
+            write!(f, "\n  {lib}: {count}")?;
+        }
+        Ok(())
+    }
+}
+
+/// Resolves imports in the PE image by writing Xenia-style values.
+///
+/// For variable imports (type 0): writes `0xD000BEEF | (ordinal & 0xFFF) << 16`.
+/// For thunk imports (type 1): rewrites the first 8 bytes to valid PowerPC:
+///   - word 0: `li r3, 0`       (0x38600000)
+///   - word 1: `li r4, <ordinal>` (0x38800000 | ordinal)
+///   - words 2-3 are left unchanged (already mtspr CTR, r11 + bctr)
+pub fn resolve_imports(
+    pe_image: &mut [u8],
+    xex: &Xex2File,
+) -> Result<ImportResolutionSummary> {
+    let imports = xex
+        .optional_headers
+        .import_libraries
+        .as_ref()
+        .ok_or_else(|| Xex2Error::InvalidPeImage("no import libraries header".into()))?;
+
+    let load_address = xex.security_info.load_address;
+    let mut total = 0;
+    let mut variables_written = 0;
+    let mut thunks_written = 0;
+    let mut per_library: Vec<(String, usize)> = Vec::new();
+
+    for lib in &imports.libraries {
+        let mut lib_count = 0;
+
+        for &addr in &lib.import_addresses {
+            let pe_offset = (addr.wrapping_sub(load_address)) as usize;
+
+            let raw = read_u32_be(pe_image, pe_offset).map_err(|_| {
+                Xex2Error::InvalidPeImage(format!(
+                    "import address 0x{addr:08X} (offset 0x{pe_offset:08X}) out of bounds"
+                ))
+            })?;
+
+            let record_type_byte = (raw >> 24) & 0xFF;
+            let ordinal = (raw & 0xFFFF) as u16;
+
+            match record_type_byte {
+                0x00 => {
+                    // Variable: write 0xD000BEEF | (ordinal & 0xFFF) << 16
+                    let resolved_val: u32 =
+                        0xD000BEEF | ((ordinal as u32 & 0xFFF) << 16);
+                    pe_image[pe_offset..pe_offset + 4]
+                        .copy_from_slice(&resolved_val.to_be_bytes());
+                    variables_written += 1;
+                }
+                0x01 => {
+                    // Thunk: rewrite first 8 bytes to valid PPC
+                    if pe_offset + 16 > pe_image.len() {
+                        return Err(Xex2Error::InvalidPeImage(format!(
+                            "thunk at 0x{addr:08X} (offset 0x{pe_offset:08X}) extends past PE image"
+                        )));
+                    }
+                    // li r3, 0
+                    let word0: u32 = 0x38600000;
+                    // li r4, <ordinal>
+                    let word1: u32 = 0x38800000 | ordinal as u32;
+                    pe_image[pe_offset..pe_offset + 4]
+                        .copy_from_slice(&word0.to_be_bytes());
+                    pe_image[pe_offset + 4..pe_offset + 8]
+                        .copy_from_slice(&word1.to_be_bytes());
+                    // words 2-3 (mtspr CTR, r11 + bctr) left unchanged
+                    thunks_written += 1;
+                }
+                _ => {
+                    // Unknown record type — skip
+                }
+            }
+
+            lib_count += 1;
+            total += 1;
+        }
+
+        per_library.push((lib.name.clone(), lib_count));
+    }
+
+    Ok(ImportResolutionSummary {
+        total,
+        variables_written,
+        thunks_written,
+        per_library,
+    })
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -118,4 +230,19 @@ mod tests {
         assert_eq!(ImportRecordType::Variable.to_string(), "variable");
         assert_eq!(ImportRecordType::Thunk.to_string(), "thunk");
     }
+
+    #[test]
+    fn test_resolution_summary_display() {
+        let summary = ImportResolutionSummary {
+            total: 10,
+            variables_written: 5,
+            thunks_written: 5,
+            per_library: vec![("xboxkrnl.exe".into(), 10)],
+        };
+        let s = summary.to_string();
+        assert!(s.contains("10 imports"));
+        assert!(s.contains("5 variables"));
+        assert!(s.contains("5 thunks"));
+        assert!(s.contains("xboxkrnl.exe: 10"));
+    }
 }