chore(ios): log full Share Extension trace on startup (temporary)

Surface the complete Share Extension execution trace during app startup
so the cold-start share path can be inspected even when Xcode truncates
console output.

In checkForSharedImageAndNavigate(), after the existing diagnostics
call, retrieve SharedImage.getShareExtensionTrace() and:
- log the full untruncated trace between TRACE FULL START/END markers
- show the full trace in a user-visible alert (iOS only)
- log TRACE LENGTH and the first 500 characters

Share-target behavior is unchanged and the trace work is gated to iOS,
so Android is unaffected. All additions are marked with
"TEMPORARY SHARE TARGET DIAGNOSTICS".

src/main.capacitor.ts

@@ -388,6 +388,35 @@ async function checkForSharedImageAndNavigate() {
           })}`,
         );
       }
+
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      const traceResult = await SharedImage.getShareExtensionTrace();
+
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      console.info("[ShareTarget] TRACE FULL START");
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      console.info(traceResult.trace);
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      console.info("[ShareTarget] TRACE FULL END");
+
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      if (Capacitor.getPlatform() === "ios") {
+        alert(traceResult.trace);
+      }
+
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      console.info("[ShareTarget] Extension Trace\n" + traceResult.trace);
+
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      const traceLength = traceResult.trace.length;
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      console.info(`[ShareTarget] TRACE LENGTH=${traceLength}`);
+      // TEMPORARY SHARE TARGET DIAGNOSTICS
+      if (traceLength > 0) {
+        console.info(
+          "[ShareTarget] TRACE FIRST 500\n" + traceResult.trace.slice(0, 500),
+        );
+      }
     }
 
     logger.debug("[Main] 🔍 Checking for shared image on app activation");